Does it make sense that although I'm okay with body positivity, that I absolutely hate being fat?
How do you feel about hating yourself?
That's a good negative emotion, you need to hate yourself in order to change yourself.
It's understandable you want to promote body positivity but you're also critical about your own physical appearance. Being overweight can drastically affect your health, you should use these emotions to start working on improving your physical health. Continuing to dwell on the negative thoughts and not doing anything about it will not change anything and your health could decline.
If I was good looking, I wouldn't act this way.
I don't know how much weight affects your attitude, but you are correct that losing weight can be good for you. You can get very sick if you stay at an unhealthy weight for too long, and I'm glad you want to try changing that.