The "-phobia" suffix has been twisted by radical ideologues to mean something it doesn't and used as an insult against people who don't exist within their echo chamber.
I don't fear or hate trans people; If a guy wants to dress up like a woman and even go so far as to have a surgery to invert his cock, more power to him. I don't fear or hate fat people; If someone wants to eat their way to an episode of "My 1000lb. life", again, more power to them.
Where I do take umbrage is when those people begin enforcing their views on the majority. The same people who scream at the top of their lungs that we need to "trust the science" on climate change and COVID protocols/vaccines are also the ones who disregard decades, if not centuries, of biological and medical science when they push their "fat is healthy!" or "trans women are women!" ideologies.
There is nothing healthy about being fat or morbidly obese and I've seen more than one discussion topic on other forums or social media outlets where people genuinely think their doctors should be delicensed for even suggesting weight loss for health reasons. I'm 40 pounds overweight and I feel the effects that has on me every single day. Anyone who argues that "fat is healthy" is in absolute denial about the medical stress they are putting their bodies under every day, and they use "fatphobia" as a way to mask their denial by playing victim.