The term hybrid is not new terminology
It's not a new word, but your usage of it is new. I have never heard anyone use the term "hybrid" to describe a human - not even a person of mixed race, for which the term would make more sense from an etymological standpoint, though it would still be inaccurate.
and I don't see why people don't want it combined with trans.
A few reasons:
1. People don't generally appreciate it when other people who dislike them (or certain aspects about them) invent new names for them.
2. It's not accurate. A trans person is not a
combination of a man and a woman (not any more than any other human is, anyways)
3. Because the term "trans" is perfectly adequate. What about a trans person is
better explained by calling them a "hybrid" than by calling them trans or transgender?
But hybrids they are if they have had surgery or hormones to switch them from one gender to the opposite gender.
A hybrid is something that takes two distinct entities (or concepts - i.e. hybrid workplace) and combines them into a third distinct entity/concept that shares characteristics of the two parent entities/concepts. A trans person is not a hybrid because, in the process of transitioning, they do not combine with a second person to produce a third distinct person. They remain the same person as before, just with some changes. Would you call someone who has had a tattoo a hybrid? What about surgery to remove a growth? Or a kidney transplant (that's actually an arguable one, but I've never seen anyone do so)?
The word hybrid is not an offensive term.
Very few terms are offensive in and of themselves. It's the usage that makes them offensive.
But trans is a fairly new term that most times has tto be written with the the terms man or woman and that creates misgendering.(by the way my spell checker says misgendering is not a word).
If you aren't sure or don't wish to misgender someone who is trans, you can call them a "trans person".
And "trans" itself is a Latin prefix meaning "through, across, or beyond" - it's used extensively in the English language: transfer, transportation, trans-continental, trans-Atlantic, and many more:
Words with the prefix "trans-" (1,000 results)
The meaning of the word "Transgender" should be abundantly clear to anyone with a basic understanding of etymology and the English language.