Why would you use Google Docs to provide the list of games instead of creating a GOG Mix? And a table with one column instead of a simple bullet styled list?
Did you just put a student to export a list from a database table and just copy paste it into a document from a Chromebook?

Let me say this coming from somebody who is, I completely assure you, the most moronic, tech-illiterate, needing-of-handholding dope on this forum:
There's a GIANT BLUE BUTTON on every game that says "TRY GOG GALAXY" that's impossible to miss unless 90% of your userbase is downloading while drunk. Nobody is somehow not seeing it, what they're doing is avoiding it. You don't fix this by trying to spoon-feed it to them and making them jump through more hoops to avoid it and wheedle them down until they concede because they don't know what's best for them. What you should be doing, if this is your true intentions, is to give them the info you've just given us here. Don't tell me to use Galaxy. Tell me WHY to use Galaxy.
Now, this would presumably be taken care of by getting people to click on the button (it's big and blue and shiny after all), since it takes you to the page that has all the info of the benefits listed on it, but if you want an alternative, maybe make the button bigger. List the reasons to use Galaxy on the installer page or something. Slap a big ol' advertisement on the top bar and the front page.

To say "well, people don't notice" is either a lie, an insult to the intelligence of the customers, or an extreme misinterpretation, given that the obvious solution to this problem would be to advertise it better, not surreptitiously slip the proverbial vitamin into the pudding. The bizarre choice to use such subtlety smacks of underhandedness and reduces the trust people have in the company.

Mind you, I imagine the majority of people won't even care or notice. Heck, most people will never even know this happened since most people don't visit the forum. They'll just install one day and be like "Oh, a checkbox? Huh.", but the problem for you guys is the implications of it. It's an easy method, I'll admit, but what does that say about the people who thought to implement it?

"We must do something, our customers aren't tech-savvy enough to click on download, double click on a file, and then click on 'okay'. It should all happen with one click or, ideally, none. Galaxy should attract more people unable to cope with such complexity."

"Hey, our forums are so full of retards that we're forced to hire a moderator now. How did that even happen ?"

This brings up another question:

Now that the installers will come with Galaxy, will GOG be getting rid of that giant blue button? It seems silly to keep it around...

Here's another suggestion. Instead of doing this, change the website so that on all accounts when selecting a game in the library for the first time a message about Galaxy pop up explaining what it is, its advantages, how to get it etc. that needs to be dismissed before download links for the offline installers are offered (and make sure that once dismissed it never returns - the big blue "Try Galaxy" button can remain should people later change their mind).

This approach has the added benefits that you don't need to waste lots of time and effort re-building and re-testing all of the installers, and GOG users don't need to re-download them (or download existing installers in a hurry before they're changed).

Even a completely new and stupid user who'd appreciate a bundled installer would only want it ONCE. There's no usage case for "give me a Galaxy installer with every game".

And next week they will change their name to GOGA.com - Galaxy or Go Away!

The store will be at store.galaxypowered.com?

We already know the (official) reason why GOG is doing this. That doesn't change the fact that the method you're using is making things considerably less convenient for your existing userbase. If you're really that concerned about new users missing out on Galaxy, there are dozens of better ways this could be implemented - many of which have already been suggested in this thread. For example, placing the 'Galaxy included' download links above the standalone installers on the download page, or including a link to download Galaxy in the install dialogue (rather than downloading all the files as part of the installer).

I realise the mods on this forum are probably not the ones responsible for this decision and don't have any control over it - but you need to bring this thread to the attention of those who are. Point out the 20 pages of angry comments, the people with over 1,000 games threatening to delete their accounts, the people joining or coming back to the forum just to say how much they hate this decision. Don't just assume that the 'silent majority' (of which I was one until yesterday) are with you on this. Like I said, the more like Steam you become in your attitudes to customers, the less reason people have to shop here rather than there.

Wouldn`t it be better for such a User to present this information in his library by adding some info under the "Try GOG Galaxy" instead in an offline installer. I guess such a not tech savvy user would rather prefer using a client to download instead an offline installer, where he probably has to find where the game is and so on?

And where is the problem to integrate the information readable and reachable for everyone? Is GOG thinking the users are not able to understand the information? There are principles and GOG gives a shit about that. That's the message. As I've said: Will have a look on this on friday. Afterwards: Quit and delete, never to return. Not to STEAM and not to GOG! Don't need those clients.

*makes a krayt dragon sound to distract everyone, then runs away*

Oh, so you'll only have to uncheck it once?
That makes things better. Still not the best, but considerably better.
As you can see, you tend to get one when you refrain from insulting and passive-aggressive commentary towards other users. I would suggest trying it. It works.