In Rome all guys do that.
My best friend, who is a really outspoken woman wanted to provoke them, once.
A group of three guys catcalled her, a guy in particular.
Some comment about her bottom and legs.
She fiercely crossed the street and rushed to him, telling him: Look, if you're a man, and if you are cocky enough, now ask for my phone number.
He blushed and apologized, his two friends laughed at him.
My best friend insisted (also because he was really cute, I admit that) and he blushed even more and said that he had a girlfriend, he apologized and walked away.
This episode should make you understand that catcalling here is just to show your own pals that you're a real man. And that you like pretty girls. If you don't catcall pretty girls, you're considered gay in a male circle of friends.
Used to be the same here, maybe 40 years ago.