Because the onus of how a man behaves is somehow the woman's fault, right? The double-edged sword society likes to cut victims of this sort of abuse down with. Suggesting she asked for it, was playing coy, and all of that other b*llsh*t.
It makes me angry too. I can completely relate to everything you described. Just sitting here, minding my own business. Not in the mood to talk. And yet, I was constantly harassed when I didn't play along. I can remember the fear and the temptation to tell the entitled guys who told me to "smile more" for their pleasure to F* off. Instead, my natural resting b* face would simply harden into something frostier. I too have been grabbed and followed, harassed for my name, number and personal information from a complete stranger while minding my own business, then threatened or bullied when I refused to comply. Most of the time, it was at the hands of men who were well old enough to know better - I in my teens or early 20's - they old enough to be my father or grandfather. Each one acting like I was obligated to chit chat and entertain, and got upset when I dared to exercise my right to say no.