What happened to the games list that the people made ?

Gone forever, they don't care.

GOGMixes are coming back, according to Linko:
https://www.gog.com/forum/general/gogmixes_removed_from_product_pages/post3

He never said they are coming back and support stated something else:

"I'm afraid GOGmixes, while still accessible, are no longer officially supported, and none of them are actively maintained any more. Unfortunately this is most likely not going to change, and we are not planning to dedicate resources towards fixing any issues with them for the time being."

I have missed that statement. If that's the case, it's unfortunate indeed.

Of course, when some of them where downright rude and badly affected sales.

Just last night, I somehow dreamt that we had GOGmixes still and didn't know it, just in some weird textual form.

My brain is weird. Not all of them were made by that "NO POLISH - NO BUYING" retard.

There was one No achievement mix, which was really rude/cringy, but if there was shred of moderation on that section, they wouldn't be gone.

No, I'd just put the blame on GOG's management hiring the sole web developer who was inclined to work in Poland, but who doesn't give a damn about usability, only whatever design fad is currently in place.

Maybe. But I'm not sure do I hate this change as other people do. I understand Outdated games list was being super handy, as well as some other, but many mixed became abandonded nuisance that weren't helpful. Or downright rude.
After all, these mixes may be done on forum posts/threads.