Guys, women dress provactivly for one of three reasons:
a. There doing it for attention
b. It's suppose to look and they want to fit in and look cool
c. They don't know better.
And as many of you men would like to think the main reason would be (C.), it's not. Girl's are mainly doing it for attention, even if they don't want to admit to themselves. They notice what attracts you, they see what society says will get a man's attention, and so, they dress accordingly. Then it's because they want to look fashionable and cool. Women have this desire to fit in and belong. So, they tend to do what is the norm. Both types will dress like this, even after they are married. So, let that kind of sink into your head.
If you want this to change, well, then you are going to have to put some blinders on and start looking for the women who are dressed modestly. Yes, the vast majority of the fault belongs to young women who dress this way. However, your actions can help in changing this.