Transgender

I can understand that sentiment, but if you ignore your social context and the way language changes and is used, you can accidentally communicate things you don't intend, e.g. in the case of "transgenderism", you communicate you think trans people are the result of propaganda and ideological brainwashing rather than a natural phenomenon, and that you do not believe trans people are what they say they are.

You can ignore and take those risks, sure! I'm not really telling you what to do, I'm just giving you insight about the meaning of words you seemed to lack. I tend to agree that taboos about words and symbols often just cedes cultural territory to the right-wing, and I am shocked by how much of right-wing language and culture is merely stolen from the left, e.g. "classical liberal" and "libertarian" are right wing ideological identities that both originated as leftist. "Anarchist" is even getting co-opted.

Either way, the problem is that the trans in-community has very little cultural power relative to the anti-trans movement, they easily co-opted the term "transgenderism" from the community and twisted it to mean something else to the average person.

EDIT: oh, you should probably know even Julia Serano who wrote an article in 2015 trying to reclaim the term "transgenderism" for the community gave up on that and by 2023 admitted it wasn't really possible to reclaim it now:

Way back in August 2015, I wrote a blogpost entitled Regarding Trans* and Transgenderism that delves into that history, and how cisgender outsiders subsequently twisted the word to make our existence and experiences seem like a mere ideology. What follows is an excerpt from the “transgenderism” section of that post. I am not sharing this in an attempt to resuscitate the word (as I don’t believe that is even possible at this point), but rather to add important historical context to these discussions, and to entreat cisgender people to not weigh in about language and issues with which they are not familiar with.

(This is from that same article I linked to above.)