The point is, it's sexist irrespective of it being a woman or a man, they are essentially saying "The man is dumb, the women are smart" and yes it may have happened to women in regular basis in Hollywood but just because it has doesn't mean it's acceptable to do the same thing to men?
That's like something you do when you re 5 years old, surely he more mature way to deal with sexism is by not being sexist whatsoever?
I don't believe swapping a woman out of the role and adding a man eliminates gender from the equation at all, if anything it enhances the fact that this movie is agenda driven, would Feig have cast a woman as the secretary in the same role? I find that doubtful, he wouldn't have because he finds it insulting as he has said in many interviews, so if he doesn't like it then why is it ok to cast a man in the same insulting role?
I mean it wouldn't even be an issue if Hemsworth as only slightly stupid or dumb but the level of stupidity on show is essentially the issue here, outside of anything but a party movie it just looks like he is trying to make an "example"