Yes, it's a significant problem. Personally I hate that often I can't just normally walk in NYC without being disturbed. There is a big difference between a compliment and harassment. You can say simple "How are you this morning?" the way it's nice and the way it's offensive. Unfortunately some men pretend they don't understand this. Not only this, but they try to turn it around and say that women who don't like such compliments are strange. It's very unfair, and yes, they know it as well.
Street harassment is a form of sexual harassment that consists of unwanted comments, wolf-whistles, "catcalling," and other actions by strangers in public areas. According to Chilean President Michelle Bachelet, "violence and harassment against women and girls in public spaces remains a largely neglected issue, with few laws or policies in place to address it." It is distinguishable from workplace harassment. More: en.wikipedia.org.
I see there's been a combining of "questions" here...
Public violence against women... while I doubt it's the problem this question makes it out to be, is definitely not to be tolerated.
On the other hand, wolf whistles and unsolicited comments... are you people kidding me? Seriously, get a life and quit responding to every lawyer's wet dream of making everything illegal so they have a life of work/money ahead of them.