You asked, they said. End of story.

If you don't bother asking them to bring stuff, it isn't their fault they ask you to bring stuff. If you didn't want to bring anything then you shouldn't have asked.

I don't find it rude at all.
Ummm excuse me....I did offer to bring something which was a genuine offer but not the whole meal. I just resent that these people always rock up with nothing and never once even think to bring something however small along just because. Clearly you have no freeloading friends....so I must seem like an over-reactor.