Well, if it was truly and unconditionally a situation where your friend declared that you should never refer to a non-binary by any given name at all but always use the abstract "they" in all contexts, your friend is an absolute idiot. That doesn't reflect in any way on anyone else though, since it is very much not to position of anyone person who actually had any kind of unconventional gender identity. Well I didn't say asking, I just said find out. In some contexts, asking might work perfectly well, in some the other person will naturally clarify the first time and that's what I use going forwards. My own real name has a similar long form I don't commonly use outside formal documents and that's how I handle it. The point is that nobody every feels especially uncomfortable (and certainly not angry) about any of this, nobody views anyone as narcissistic, it's just a normal part of human interaction that we all deal with every day, sometimes without even noticing. There is no reason questions of gender pronouns couldn't be handled in the same kind of way most of the time. A few people (including some transgender people) will make things more complicated (intentionally or not) but the vast majority of the time, it doesn't need to be anything more difficult that coming to know and using someone's preferred common name. Doesn't that work both ways though? Shouldn't you put in a least a little effort to put other people at ease by understanding and using the names and terms that put them at ease?