X now considers the term “cisgender” a slur. On Tuesday, the platform reportedly began posting an official warning that the LGBTQ-inclusive terms could result in a ban from the platform.
I think it's funny that you want to do a poll for context but your question itself is context-dependent. Any quality of any human, inherent or adopted, can be a slur in the proper context.
Is 'trans' a slur when it's Elliot Page talking about himself? No.
Is 'trans' a slur when a bigot calls someone 'trans' to insult them because they think being trans is worthy of contempt? Yes.
You illustrated the point better than I had the energy to do-- I simply don't care enough to be that eloquent because the majority of what I get is nonsense in return. So instead of wasting my time, I chose to take the lazy route and encourage people to come to a consensus on this one key point so that the point you made would become irrefutable.
Neither trans nor cis are slurs by default, but anything can be a slur if used in a derogatory manner-- I think some comedian had a bit about this, but I can't recall who and I'm sure even if I did there's a good chance someone would give me a nasty label for saying such comedian made a good point....
But the same people that say trans can be a slur, cannot deny in good faith that cis cannot be a slur. They are both simple classifiers with no basis on prejudice. But some people will still argue they are slurs simply because they are used prominently in derogatory contexts.
That's not the issue. The issue is that Twitter acts like it is automatically considered a slur, rather than something that is only a slur in certain contexts.
There's also the matter of Twitter doing very little about the Nazis on its platform other than giving them a boost.