So true... they even look down on some metal sub genres, often mainly because they have some sort of melody and/or real singing in them.

My opinion on metal is that it is a material (or, rather, a class of materials), not a genre of music.

What about pop? Is it a beverage or a genre of music?

Since no one responded to your John Cage question I'll take a try.

Iirc 4'33" is commonly misconstrued as "just being silence" but I think the point is actually to have people focus on all the sounds around them, which comprise the "music" of the piece and result in a unique performance every time (which is ironic, given the popular conception of 4'33" just being that time length of silence, the same always).

Is 4'33" "music"? It strikes me as more of a performance art. Regardless, if "noise" of a room is okay to count as music at least when "played" as a piece, then why not also genres like "noise music" (which people also debate)? For that matter, isn't what you may deem too guitar-heavy, too percussive, etc, something that could just fall into "noise music"?

Music can be objectively good and objectively bad, it's possible to enjoy bad music and dislike good music. Subjective feelings towards the craft don't change the quality of it.

Most people can't recognize objectively good music even if it kicked them swiftly in the ass and teabagged their hamster to submission.

Something I should point out is that the problem with things being too guitar heavy is really an issue with the electric guitar; replace it with an acoustic guitar playing the exact same part and it becomes manageable. I actually did once see a performance of (IIRC) Jason and the Technicolor Dreamcoat, but with the electric guitar replaced with an acoustic guitar, and the result was much more enjoyable to listen to than the original (in the parts that originally had electric guitar, of course). The Battle on the Big Bridge example is another; the FF5 version I dislike, but the FF12 version I actually like, even though the only difference is the instrumentation.

(Conversely, if you took one of my favorite pieces and transcribed it for electric guitar, the result would likely be something I can't listen to without a headache.)

As a side note, the heavy metal version of 4'33" doesn't bother me because, although the ensemble includes an ellectric guitar, the guitar is tacet the whole piece.

(Another note: There's nothing about the piece 4'33" that would prevent it from being performed by the empty ensemble, that is, the ensemble that doesn't have anyone in it.)

Edit: To come later, some comments about aleatoric music and other modern art music.

Out of interest, what qualities would be considered to make a piece of music objectively good?

I don't like the Beatles.

The popular unpopular opinion. ;)

"Through the Fire and Flames" is great... on a piano.

I can deal with jazz music, but jazz fans are the snottiest music fans of them all. I loved my grandpa but he was a jazz fan and would gladly tell you every chance he got that all forms of music (yes, ALL) are useless bullshit next to the brilliance of jazz :p

I tried to find (with google and youtube) the kind of jazz I specifically hate. I thought it would be "modern jazz" but then in Youtube that is not what I meant.

The kind of jazz I dislike is kind of anti-music, not music at all. It has no real melody IMHO, just random notes one after another (or so it sounds to me).

Also, for me the power of music comes from the feelings that it creates in me, be it happy music, sad music, adrenaline-pumping action music, aggressive heavy metal music, eerie music, romantic music etc. Anti-music jazz doesn't make me feel anything, it just... is. Random notes.

Rap is a close second of the kind of music I don't like much, but at least I have heard some rap music I liked, and it can create different feelings in me.

Nice piece! Normally covers of this one are just ways for some to prove their skill, but this really is nicely done... Well, except one part that really doesn't seem to work on piano.
Even if you take it as a subgenre of rock, it'd still count as a genre of music, wouldn't it?
Reminds me, wasn't that taken as a defining trait of punk back in the day, having no musical quality?
But about metal, heh, and see when you overwhelmingly listen to metal, but only to the most musical subgenres of it (symphonic, usually female-fronted; vocal-centric, "soaring", power (in truth, most "symphonic" really falls here too, since they use synths for it, but...); non-growly gothic).

Oh, reminds me:
Grates me too, but got used to it. When it's pretty much the foundation of the genre you listen to, you make do, and it does have its place in the mix, but I very much prefer it if they tone it down, and do without the solos altogether (no drum solos either please). Pile on the bass, absolutely, but a song led by an electric guitar (not to mention two) is... harsh on the ears, and guitar solos way worse, especially when they get to high notes.

That's where Nickelback sucks memes come in. Nickelback isn't the worst band in the world. What they are, is an unholy evolution of yarling radio rock mediocrity that fails to stand out in most ways. So, what they are, is the most mediocre band in the world. (In my opinion.)
Speaking as someone who sang in a hardcore band, they ALL feel the need to have tryhard logos for a major reason. It looks good on a tee shirt, which is where a lot of struggling bands on the come up get their money from. Merch, merch, and again, merch.

I had a buddy that worked A&R for Sony Columbia and helped push bands like Coheed and Cambria, and I learned a lot about the marketing aspect of branding bands like that. Of course, they never take into account that there's nothing new under the sun and it's been done before by better artists.

In the case of Jazz, there is some Jazz that is just dull and just isn't interesting to listen to.

For an example of dull Jazz that just doesn't really do anything, take Dave Brubek's "Time Out" album, and pretty much any part of that album that is in 4/4 time is rather dull and uninteresting. (Those familiar with this particular album will realize that this flaw doesn't ruin the entire album.)

By the way, random notes actually does make me feel something; if you take random chromatic notes, the feeling is a rather strange and tense feeling, while if you restrict yourself to the pentatonic scale, it actually sounds decent. (By random, I literally mean having a computer generate random numbers and converting them into MIDI messages; yes, I've actually done that.)

If you took orange as a subgenre of rock, would you count it as a genre of music? That's how I sometimes think of with respect to metal.

More seriously, the whole genre of rock is not something I can listen to because of electric guitar and the singing style; I'd rather listen to operatic sopranos singing at the top of their lungs, at the top of their range, and slightly out of tune.
I just avoid any genre where that instrument is the foundation.

Unfortunately, during normal times I can't do so because so many public places (including grocery stores and restaurants) insist on playing such music in the background. (I have been lucky with the pharmacy at the doctor's office; they tend to play classical there, which doesn't have the issue.)

By the way, how do you feel about the high notes on the opper woodwinds (piccolo, flute, clarinet)?

They sound more... natural. Rather make me think of birdsong? But since I hear them sparingly, that may have something to do with it too? First one I thought of...
I'm very fond of very high vocals though.