Sex positivity means many things, but it does not mean that all sex is positive or enjoyable.
I am going to pedantically argue that last point. Because while there’s nothing wrong with disliking sex, it is objectively inferior to enjoying sex. After all, engaging in sex can have a multitude of benefits, be they medical, emotional, or even just the simple propagation of our species.
Not liking sex = Fine.
Liking sex = Better.