Why men can't be taken seriously you mean? I don't know who this Carla Homolka person is, but if you had a post comparing every woman to their actions on the basis of their sex I'm pretty sure you would get women defending themselves in exactly the same way (assuming this person did something terrible from context).

I'm not sure how you don't see that using "you people" in this way is acceptable in generalizing any other group. There's definitely a pass, socially, when aiming those words at men. Ask yourself why that is.