Sometimes the guy is honestly trying to give an innocent complement with no intention. But when an innocent complement is given by a stranger who is bigger and stronger than you in a situation where you have no escape, it’s hard to take at face value. Just imagine if Godzilla was giving you the same complement. Do you feel threatened?
I saw a womens college basketball player get catcalled once. She smiled and waved. She did not feel threatened because she could definitely kick anyones ass. There was also a show that dressed up moms and walked them by catcallers who were their sons (who didn’t recognize them). If you’re just giving a complement, what’s wrong with saying it to your mom? (the moms smacked the crap out of their sons)