As a qualified Turkologist I'd say no - they're not much more cancerous, they're simply more dumb. A bunch of imbeciles ? Yes. Loads of Zeka Fakiri ? Absolutely. But cancerous ? No, not really. No one can take that away from Americans, Poles & Russians.
From my experience, Turks who play this game are mostly kids who don't speak two words of English. So it is perfectly understandable for them to seem and act dumb. Poles are a bit crafty but not so bad when you're on their side hahaha. Americans are very chill, even more in game than on this forum. It is very enjoyable playing on NA servers. Canadians are the most chill out of them all.
By far the worst specimens I've encountered in this game came from Germany. Some are great (like of Torben), some are alright (aka Paul) but damn, some are pure unadulterated cancer (that craplord who permabanned me, Erzengel something).
Edit: I was chatting shit about players with extraordinary bad personality coming from Germany and completely forgot to mention kinngrimm... yeah few truly bad seeds coming from that country, enough to taint the view of whole nation hahaha