I wonder too (as some have suggested) if it was some kind of defence mechanism so people wouldn't keep asking. My DH works with a load of women (about 15,) and only one other man who he doesn't see often, as they have different shifts.
They have a Christmas party every year, and a mid summer staff get together, and he is always asked. He usually goes, but he hates it, as he has nothing in common with them. Plus he doesn't like some of them as they're gobby and opinionated, and you can't get a word in edgeways!
When he said NO to the Christmas do last year, because it fell into his time off he had booked (15th December to the 29th,) some of them were utterly incensed. They nagged and moaned and whined and damn near bullied him til he said yes. (It was £13 each and was paid for by tips they had received in the last six months.)
He said yes to shut them up, but never had any intention of going, as he had booked the time off specifically to spend time with family and close friends, and had the whole 2 weeks sorted and planned.
The party was 19th December, so he just deactivated his facebook and switched off his mobile phone for the entire Christmas break after that, so no-one from his workplace could contact him. (They don't have our landline number.) Also, we live 25 miles from where he works, and in a tricky place to get to, so they weren't likely to 'pop round.'
When he went back to work, they asked why he never came, and he said he had a migraine. When he reopened facebook, there were messages from 7 different people, and also a dozen messages on his mobile phone - some from the night of the meal.
Needless to say when they asked him to the 'summer do' (late July,) and he said no immediately, they didn't badger him this time.
So, as I said, it is quite possible, that the person in the office was so abrupt and snarky as a 'defence' thing. I expect she doesn't want to go, and probably thinks if she is so snappy, people won't keep asking. Some people in workplaces can be very pushy, and very rude to you if you are a person who doesn't like to socialise with work colleagues.
As someone said earlier in the thread, people who prefer not to go to work do's get called boring and anti social and all sorts of names. So it's kind of almost understandable that you may occasionally get someone being arsey and rude, as they are probably expecting a barrage of 'don't be boring!' type comments, and they have probably had a bellyful of them.
Still, her reaction was rude to be honest.