you may be as tall as some men but most men are physically stronger than you. an average or below average man can bench press more than most women, unless the woman takes steroids (testosterone).
my aunt is a feminist for NOW and she's head of the division to stop domestic abuse. i don't see how feminist (in general) can speak out against domestic abuse, which implies men's physical advantage in strength over women, while at the same time want to promote letting women do physically strenous work.
if you were a construction manager, would you get more productivity employing a certain number of men or certain number of women. unless there was a task to count a lot of screws, then for that task it wouldn't matter whether you hire a man or woman.