Personally I would say that it is neither right nor necessary, as it serves no public service. That's the short answer. A reporter might argue with that, so a more complete and analytical way of looking at it might be:
Q - Is sexual orientation personal or public information?
A - I think the answer is obvious (personal), but if someone disagrees then we simply have to ask:
Q - Would revealing this information affect the public interest or the individual's (which includes their friends and family)
A - There may be the odd exception (I can't think of any though) but I think it's clear this only affects the individual.
Ok, now that we've established how to tell if there is public or individual impact:
Q - Is it "right" to report personal information that has no public impact?
A - Again, I think this has an obvious answer - a definite no.
If anyone can see a flaw in my logic I'd love to hear it...