There is an old idiom that goes "everything is about sex except sex. That's about power."

Catcalling is about expressing power over someone else body and life. It's a veiled threat, coached in sexual terms. No one doing it actually expects to have sex afterwards. Its about saying "i can force sex on you. I can take control of you. Your life belongs to me."

A lot of the men engaging in it above are doing it because of peer pressure, normalized misogyny and the "thrill" of getting an acknowledgement of that power by scaring women. I dont think most of them want to attack women outright to begin with, but it normalizes mixing sex with violence and dehumanizing woman.