You understand that these are different things. You understand that they can legally be treated as different things. Well done.
[Edit: For whatever it's worth, I think the parent comment was mistaken but not worthy of being flagged.]
I wonder how we would react if the person were a man, and weren't that presentable.
It's very, very hard to say when it becomes offending/harassment. There being clear cases like the linked video in the article, doesn't change this.
I'm not saying that that guy in the video should get away with it just because we keep bike-shedding about where the line is, but it is something we need to think about as well.
Sure, sometimes it might work out fine for both parties. In almost all cases it doesn't. If that woman feared retribution due to harassment laws, and she wouldn't have approached your wife, then the world now would be poorer by one anecdote, but at the same time much safer and more welcoming to billions of women. It's not a hard choice at all.
That's not a defence against another person behaving questionably.
Anyway it's generally understood that there's differences in the appropriate behavior of men and women. For instance, it's okay for me to come up and piss next to a guy who's pissing but probably not okay for me to come up and piss next to a woman who's pissing.
So even if her behavior was accepted as reasonable however odd it was, it's not proof that every guy doing that would also be accepted as reasonable.
You're not responsible for the behavior of other people, but you do have to take into account other people's behavior (to the extent it's known to you) and your own past behavior, when you're deciding how you should interact with other people.
These aren't new ideas. They're the basic principles of manners that have always been part of our society. Criticise pushing them into law as much as you want: but don't act like they're coming out of nowhere and impossible to comply with or enforce.
This law is clearly not targeting any potential romantic interaction between strangers on the street. “You’re attractive” can be harassment in a workplace setting (where power dynamics and standards of professionalism are different) without being harassment in a different setting.
This law is targeting catcalling and men who will follow a woman down the street. These behaviors are power plays and are intimidating in a way that a polite and respectful approach is not.
You may never have been the target of such behaviors, but if she travels frequently on foot, your wife almost certainly has been, and can likely tell you just how awful it is to be the target of them - ranging from disempowering to mortifying to terrifying.