AITA for telling my enby friend their pronouns aren't real? : AmItheAsshole

My friend identifies as non-binary and that's super awesome. They go by (or used to go by) they/them pronouns. Today they told me that they're going to start "nounself" pronouns. I was really confused so I googled it and found a tumblr blog about them. Apparently it's using an object as your pronouns. They said that they wanted to start going by "egg/eggs/eggself" pronouns. Look, I don't even mind using ze/zir pronouns or whatever, but I draw the line at using the word egg as a pronoun. I told them that they shouldn't do that and just go by they/them because that seems the most simple. They responded by saying that I was being really hurtful and that pronouns are the most important thing to trans people and that me saying that really upset them. I basically just said "look, I'll address you by your name if you don't want to go by they/them anymore, but i'm not calling you an egg ffs". They left me on read and I'm just wondering if I really need to apologize for it. Personally I just think they're overreacting and will get over it soon, but I don't know? Am I the asshole?