The only way for (straight) men to try to understand how this feels to women is to imagine if a much larger man said the same thing to them. People try to reverse it and ask what men would feel like if women catcalled them and that doesn’t tell you anything at all. Men don’t fear for their safety with strange women. Men don’t fear women, period. Many men say, “That would be awesome!” Or, “It wouldn’t bother me.” Why would it? You have little to fear from a woman on street approaching you.
But if you run each scenario through a filter where the man is the recipient and the catcaller is a much larger man, you may start to see what it might feel like. If you are a straight man walking down the street in a big city without many other people around and a big dude you don’t know walks up looking at you and says, “Hi handsome. Looking good today” and just stands there like he’s expecting something, I think you would be freaked out. If you give him a strange look and keep walking and he follows after you saying, “What’s the matter? You think you’re too good for me?” Okay, what if the anger and following only happened 25% of the time? Would you not still be on edge every time a stranger approached you? What if the big man said, “Well you could at least give me a smile”? What if a group of big men all stopped talking to each other and stared at you as you approached and then when you had passed started making loud comments about your body? Or if they all started wolf whistling? I’ve experienced all of the above multiple times. Granted it’s much rarer that a strange man says something like, “Come here and sit on my face!” I have experienced that as well.
In my experience a lot of men would consider it fighting words if another man on the street said, “Nice ass!” or some such. Or if another man patted your arm as you walked by and said, “Hey gorgeous, where are you going?” Or if a stranger actually darted over and patted your ass (also happened to me once.) As a man can you even imagine these scenarios happening to you? Would it make you uncomfortable or would you be “happy for the compliment”?