No, it's sort of the opposite. "Not all men" in this case would be "not all companies have cultures like this". The response to "not all men" is "but (practical

No, it's sort of the opposite. "Not all men" in this case would be "not all companies have cultures like this". The response to "not all men" is "but (practically) all women have experienced harassment". So in this case one might say "even if not all companies do this, all employees have experienced it". And mod's comment is that at least one employee has not.