Not an assumption. While there are some that can be good clan mates, the vast majority if you really take a look at the stats are usually just a lone wolf. I not only look at time in game and # of games but the whole stat record including achievements. I just turn down an application (with unicum stats) because while a very strong player was a bit of a butt. So I declined...he was none to pleased...had to block him.
My background/career was taking all known facts/observations to try to draw to a conclusion.
I've really started to not look kindly at applicants that were in too many clans...usually an indication of a tumbleweed.
I endeavor not to assume, but to make assessments.