I usually get a bitfender warning that the russian site has bitminers.. adds that run on the background processes of the page have minners that use your GPU to farm bitcoin... unfortunately this is a very common way of websites generating revenue.. even some bigger sites we all know and trust use these miners.. rumors have it that Aliexpress is big on this.
Yes the reason for all mods WS supported or not end up on these sites is because of cracked versions.. I'll admit that I've cracked a few games in my time and original spintires was one of them.. at that point modders were still uploading their trucks to the web. the games was too good to not to be bought though.
To try to justify my cracks it's to just try the game, if I like it I'll buy it. and most games I play don't have mod support or are older than most of steam users..
I think it's a terrible thing that the mods are being ripped and I hope that we can find some way of stopping this.