@lina I'd agree that you shouldn't have a single identity online, because you don't have a single identity offline, either.
Nobody "is the same person" while cuddling in bed with their spouse as when their boss says "come to my office", just to take a couple of examples.
Here's something I wrote back when Google Plus existed, and was trying to enforce a "real names" policy (or back during the NymWars, for those who remember that word…): https://kagan.mactane.org/blog/2011/07/17/how-many-identites-does-a-single-person-have/