My understanding of nonbinary is it, in practice, most commonly means "person for whom it is very important that others do not assume they share the stereotypical traits of their sex"
hmmm idk why this seems wrong, i think opinions about perception is like... usually part of it but not actually necessary? like a lot of enbies are like "oh since we now culturally have the option of going by they/them pronouns, i'd prefer that" but dont otherwise care much
but probably when one sees an enby *in practice* (pimply plane.jpeg?) then it's bc it's very important that others don't assume this
bc it takes a lot of effort to successfully signal being a gender that's not really recognized by most people
fwiw to me personally I do not parse enbies as a third (or neither) gender, in my view they are exactly their original gender and trying to do something different that would probably be better described as not actually having to do with gender
like "unfeminine woman" seems like a more appropriate descriptor than "not a woman" for all the nonbinary afabs I've met.
Also nonbinary ppl much more closely match cis ppl of their birth sex in all my surveys than other enbies of the opposite sex, minus stuff like politics
it's hard to pass as the opposite sex, trans ppl put in a ton of effort to this. generally if you don't pass the best u can get is "it's unclear what bio sex they are", and it's extremely rare I've felt like I couldn't tell. usually when that happens they're trans ppl
I assume your friends don't know how you actually feel about non-binary people. Anyway the responses to your tweet are why I avoid people as much as possible. I don't really believe non-binary people can have relationships with people who aren't non-binary as most don't get us.