Was it dismissing or just not understanding?
Some folk require understanding before they offer acceptance. Those folk will frame it as “just not understanding”. I frame that as lack of acceptance. Acceptance isn’t contingent on understanding. You or I not understanding an aspect of someone elses identity has nothing to do with the validity of their identity.
If you wish to ask someone questions about their pronouns and identity, you’re welcome to do so, but remember they don’t owe you an answer, and whether they offer you an answer or not, and whether you understand their perspective or not, either way, gatekeeping and invalidating their identity is not on.
they are so uncomfortable to use that it just makes me not want to address someone who uses them
That was the other option I offered folk. If someone has stated their pronouns, either use them, or if you can’t bring yourself to use them, don’t engage with the person.
If the person is trolling, report them. But even if they’re trolling, the above statement still stands. Respect their pronouns or don’t engage with them as you report them.
I'm trans. Cis people literally can never truly understand my experience or why the things that are important to me are important. Acceptance can't be contingent on understanding they can never have.
Neopronouns are the same. You can work on your own understanding to reduce your discomfort but your discomfort should be your problem, not something you get to force on to others