Why are men with big butts are laughed at, but women are aren't?

To be fair, it's only been a hot minute since women with big butts were likewise laughed at. 

Well it's not natural for a male to have a big butt and society might think notice he is either fat or just have noticeable flaw

Come on. if I had a nickel for everytime I laughed when my buddy pointed out a woman with a huge butt and said damn look at the shitter on that critter! I think it happens to women just as often.

they r not, they r  respected by other shot put throwers