George Costanza: Was that wrong? Should I not have done that? I tell you, I gotta plead ignorance on this thing, because if anyone had said anything to me at all when I first started here that that sort of thing is frowned upon... you know, cause I’ve worked in a lot of offices, and I tell you, people do that all the time.
Yeah, that's pretty much what's going to be the official "explanation".
However anyone who has actually worked in the real world knows you don't use personal email for business, unless you own it.