They don't support what they sell

They don't make what they sell, either.

Why would you waste your time on the GOG forums complaining if you weren't wanting to buy anything from GOG?

If there's a problem contact support, they are really helpful.

More explanation would be helpful.

You do realize Steam does not support what they sell either (with the exception of Valve's own products). Supporting games is the responsibility of game developers/publishers.

You use a store because you believe that they give you the best bang for your buck. If you think a different store gives you a better deal, go with the other store. Basic rules of purchasing anything.
As for support, they should be supporting their products. There are cases when support takes a while to reply (mostly on bigger sales or with more complex issues), but they are usually good at their jobs.
Still, if you don't find GOG's offer good enough, then don't buy from them.

Refer post number 3.

Some vendors stand behind the products they sell.

Get a refund then.

I presume you don't buy games from Steam either then as Valve supports games sold on Steam even less (except games made/published by Valve itself, and even them pretty slowly, like how the cat-bot cheat bots are now running rampant on Team Fortress 2 while Valve just fiddles its fingers).

https://www.youtube.com/watch?v=OE9nlBMHOSs

Because the installlers you can download are more convenient than steams.

I have actually seen that video, but wasn't it only about taking advantage of cat bots not shooting at you if you don't act aggressively, but just "taunt"? The authors might just as well remove that feature from the bot so that it shoots at everyone no matter what they are doing. Plus, it doesn't really solve the actual problem.

The other day I noticed though that for some reason cat bots don't seem to attack sentries, so I guess you could always play an engineer and hide behind your sentry crouching. Or at least at one point when a cat bot shot me when I was playing an engie, I was just able to start building a minisentry next to it before I died. For some reason cat bot didn't seem to care for that sentry, and when the sentry was completed, it just killed the cat bot.

I have no idea if that is intentional, someone online claimed cat bots "can't see" sentries.

Also cat-bots still seem to have issues on many maps where they appear. E.g. on Turbine a cat bot was advancing in a vent sideways, and while I was on its side in the same vent, for some reason it was unable to shoot at me. So I killed it instead (I think I was either a pyro or a soldier).

But on e.g. the Harvest map cat bots are pretty much a game killer.

Troll thread.