And it was literally just so they could skinnerbox people and sell skins. I still remember when if you wanted a skin you just downloaded it and could put it on your server and anyone who joined would download and use it. People running their own stuff makes DLC/lootcrate/cosmetics unviable and I do think a huge part of the "server" finding stuff is to algorithmically put you in situations you are likely to win/lose at certain rates to keep you playing. Anything other than community servers as the primary avenue is a dark pattern. You also lose out the path to getting into modding/3d modeling/programming/running servers that those modded servers were for lots of people including me.
If you have fun instagib servers that might detract from how many lootcrates people buy since they might just get curb stomped in it + it's just harder to track and measure the impact of changes when you are minmaxxing for monetary extraction when you have high variety of mods/servers. If you want to track and evaluate player behavior to manipulate it you need to control for as many variables as possible. These game companies are straight up evil.
On the other hand, during the anarchy years of bring-your-own-skins (and sprays), there was a lot of horrible shit out there — goatse was only the tip of the iceberg.