You call it "kindness" I call it social conditioning. I do not accept the idea that there are more than two sexes (or "genders" if you prefer) and will never use preferred pronouns. Trying to force me to do so under the pretext of "kindness" is a roundabout way of making me accept something that is not true.
It's possible to not believe in something and still be nice to those that do. I don't believe in god but I'll still wish people happy Easter/Hanukkah/Diwali/etc., etc., etc.