What is the point of these surveys when we know how many "level farming" operations[1] are going on in China, etc.? Casual CSGO has become unusable these days. Of course, apart from farming operations, cheaters come from across the world. And AFAIK, most cheats software is available only for Windows. Valve's esports-grade games like CSGO, and DOTA2 are free. There is no penalty for getting banned in such a context. It is easy for the "farmer" or cheater to create a new account, and start playing again.

I would be more interested in knowing what percent of paying customers run whatever OS. This info would be useful to new game developers too.

[1] I won't post links because my comment might get auto-flagged as spam, but interested readers can find them easily by searching for something like "Buy CSGO High Tier Accounts".