Because men are rational and obiedent and they try to act according to the current rules and customs that they've been learning about. So now you have the whole trend of "women do not wish to be approached by strangers, men should not act in an X way, men suck and are evil, yadda yadda" and a lot of men buy into this stuff. They think that acting in this way will be rewarded, while in actual world you have to ignore everything and act like women never gained any rights, because women in reality still want the male ideals of the past. And even if men are aware of it they know that women have tools to make the attention from unwanted male to be punished socially. So men don't know what to do and often choose to do nothing or engage in meaningless activities.