I find it niggerish behavior. There are more appropriate ways to let a woman know you are interested.

Yes and no, it's a female thing. If they find you attractive they enjoy the attention. If they don't, you're a creepy pervert. They did a study on dating sites with a model pretending to be a pedophile. Women almost always were able to excuse this behavior because they found the pedophile attractive.

Don't be unattractive.

Generally it's uncivil behavior even before feminazis tried to make it an issue, I wouldn't cat call a woman on the streets, i might stare at some fine ass passing by but im not gonna holler at her, if I just needed to try to get to know a passing woman shouting or a big whistle call ain't gonna get any worthwhile woman going, I'd approach her but I can't imagine the need being so great in just passing a woman by. My issue with how this was handled is that its now bad form to approach a stranger on the street, that's sad and unhelpful and this whole issue has reinforced the mass hysteria in women that white men are somehow particularity dangerous.

All that said it's a different story if you cat call a girl or woman you know, the situation must be right for it but cat calling a girl in highschool became a daily ritual for her and I and when her parents let her date I became her first boyfriend. This was at a nice christian school, before the cat calling BS, she was a friends cousin and later I found out an aunt's niece through marriage so we were third cousins twice removed by law, no blood relation. Anyway she was maybe the prettiest girl in school, grew up with her grandpa and was shy as could be, she heard me say to her cousin how pretty she was and decided that instead of being embarrassed I'd give a wink, she blushed, and every time I saw her coming from the lunch line to sit down I'd say to my friend sitting next to me a compliment meant for her loud enough anybody nearby could hear it, before long she'd get pouty if I didn't notice her or sat down after her and come sit with us.

It was a cute immature thing you could do to allow a girl a safe social distance to be paid a compliment but you could rapidly make it a disrespectful thing if you took it too far.

Catcalling is for whores and women who are comfortable with you(who aren't married to other men) women who get off to being catcalled are simply comfortable with semi aggressive flirting from the man in question either because they know the man and it fits their social context or because she would fuck a stranger/desperate for sexual validation steer clear, if you are over 6 foot and dress cleanly but have the physique of a wwe wrestler cat calling might be a valid pick up strat if all you care about is pussy.

Catcalling was attacked as a part of the bolshevist movement in the west, bolshevism is defined by persistent victories without persistent victories, no matter how petty, the movement crumbles they use this momentum and drive for victory to motivate their useful idiots and keep them energetic but also to demoralize their detractors that's why they lose their shit when you challenge them because any defeat could start a losing streak and set them back years it's why defeating gamergate was something they were willing to lose a half a dozen publications and all public trust over because winning after going all in is the best sort of victory for their means.