I'm gonna play devil's advocate here --
Was it personally devastating? Yes.
Was this person amazingly blunt? Yes.
Do they maybe have a point though? Yes.
I say this with complete sympathy to you, and the knowledge that I too would have crumpled and walked away -- honestly, that's not a fight worth fighting. If they don't want you there, you don't want to be there.
Here's the thing -- speed dating is something that is hard, on a social skills level, even for NT's. It's like being at a very social party with the fast-forward button pressed, new conversation every few minutes.
The people running these events have responsibilities to their paying customers to make sure that they keep the experience as smooth as possible. Someone whose social skills are poor will not be able to keep up, and will literally be a boulder in that river of conversation they are trying to create.
Think of it as being a pro swim meet -- would you let in someone who couldn't even swim? Would that not detract from the overall situation?
My advice -- find another venue. There are plenty of ways to meet people and get dates, but speed dating is not for the faint of heart or the low-skilled. Join a club, find an organization, take a class -- leave the speed dating to the "popular," chatty, douchey people. Honestly, I'm not sure why you even were interested in speed dating -- kinda sounds like torture to me, if your social skills are not your strong point.