Women fear
when men whistle at them because occasionally one of those men
attacks them physically.
I can understand how this danger teaches women to react to whistling
with fear. It is considerate not to whistle. It does not follow that
whistling is wrong.
That a fraction of people that do A also do B, where B is wrong, does
not imply that A is wrong. It would be unjust to criminalize whistling
because of what a small fraction of whistling men go on to do.
I wonder, though: if we could end misogynist violence against women
on the street, would women cease to feel frightened by whistling?