Why do women exercise like this?

It's really confusing. So many women are willing to work so hard, but they do almost everything wrong at the gym. I don't understand why women exercise with 4 types of arm exercises and 30 minutes devoted to chest exercises. That only makes people bigger (which is fine if you're a bodybuilder, but most folks don't want that). And why do women do bicycle cross crunches? Those don't work. And