I have to question this.
Name me one actual esport that have this rule, please.
Some, like CS GO, showcase the name of the players sometimes, along with theit GTs,, but nobody (I dare say) calls Get_Right Christopher Alesund during streams.
There's a difference between esports and "real" sports, and esport should, from a marketing perspective, keep the differences between the two forms of competition to differentiate themselves from the other.
I do agree regarding the more obscene gamertags, though. They dont help any scene that wants to be taken seriously..