I don't necessarily think the concepts are out of line, but the way she's put it is rude.

Personally, if I invite people to something then I provide the food. If it's a 'bring a plate' kind of thing and there are dietary requirements, that's fine, but it's nice to be asked. All those things should be included in the invitation.

we had a gift registry for our wedding, as that way we could help people choose things we would like. There were some people who couldn't use websites, so they bought us something else, which we were also happy with. Gifts are a nice to have, not a must have. Saying that, I can understand people not wanting 100 of the same thing, but, as with all registries, there should be items at different price points to meet different budgets.

maybe if she was a close friend, you could talk about how it has been handled. Some people don't have great social skills. If she's just a self-absorbed cow though, then no, I wouldn't go either. Life is too short to accept being treated badly.