Psuedonyms have always been a dicey subject for me, and I have to take it on a case-by-case basis taking into consideration why a given person is using a psuedonym.

Preservation of privacy is a reason that's above reproach...if it's the only handle a person uses. But using an alias for another well-known online name complicates things because of the inevitable Jekyll and Hyde effect (or purpose)--as you said, "I may be a little more insulting under a pseudonym than if I used my real name". The word "may" is a bit ambiguous in that sentence, which hints at the problem--are you making a prediction, or granting yourself permission?.

Seems like the use of an alias is often an attempt to create a "deniable persona", and I have to take a dim view of that. In the immortal words of Stewart Brand, founder of The Well, "you own your words".

This is a judgment call, like all such cases, and it sounds like the preponderance of your motivation really is to preserve your privacy from work. But watch the profanity in subject lines, "Buster". Try not to let your two personae drift too far apart.