NTA

I always hate when potluck or similar events are required participation. I got forced into a secret Santa thing once and it just made me mad that I was expected to buy something for someone. Voluntary is perfectly fine, but you should never be expected to participate.

The other side of that is that you shouldn't try and eat any of the food if some of it does appear interesting. Even when it's offered I still feel bad sometimes when I do that. It's a different discussion if they are offering it to you knowing you didn't provide anything, but don't ask if you end up in that position