Some of it's definitely a power and cruelty dynamic... but you might be surprised by how much of it just because some dudes are the dumbest motherfuckers imaginable.

It’s definitely a power thing, it’s pathetic worm behavior.

Asserting dominance?

This one.

Being a weird creepy sex-pest: women hate you

Being nice and treating women like humans: women like you

Wow, who would have thought!

Because they constantly need to reaffirm their masculine role in society. They do this to make sure they are Very Male, totally not gay when they are among other males but they also behave like this when they are alone to soothe their insecurities. One way of doing this is to "remind" women of their place by degradation, to them masculinity is being always on top and active. It's about making women uncomfortable on purpose, the catcalling phrases ranges from stupid to straight out obscene just for the sake of reaffirming the power structure of heteronormativity. A male always gives orders, a male always penetrates and never gets penetrated (consider sex positions, the penetrated is usually below and "passive", both literally and metaphorically). In some cultures even performing cunnilingus to a woman was/is considered "effeminate" and being accused of performing it on ancient Rome was the today's equivalent of being insulted with common pejorative words questioning the masculinity of the person performing such act.

EDIT: use of derogatory language.

sometimes I see someone looking nice and I wanna be like "hey! you look good in that outfit over there!" but then i have to stop myself so im not part of the problem

Patriarchal domination