I don’t think the person on the left’s a transphobe, but I also don’t think they understand the scale of the harassment trans people face on a daily basis. Like it’s so bad the users would rather just have potential trolls ignored and downvoted than to see well meaning cis people come in and do vigilante justice using the same tactics of abuse trans people go through every day.
That empathetic disconnect looks like transphobia to some users. I don’t know that the users are right, but I understand how you reached that conclusion, especially with the person on the left’s days-long soapbox crashout about how despotic Ada is.
I don't think that's a dumb thing to ask at all! It might be that queerphobic is a better term. I don't know the best term for the fear or aversion to identities outside of the binary/non-binary that most are accustomed to. I personally tend to put that under the transphobic umbrella.