It's okay, as in usable, but it realllly bugs me. I'd take 500 "he/she"s over one "they". For someone graciously accepting the title of "grammar nazi", though, I must admit I don't look all that far into these things. If Strunk and White don't have an opinion, neither do I. On that same note, I think White was big on the whole "assume 'he' when gender ain't specified" thing, but I'm sure that's been edited out by now.
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i'm a rainbow too.