That's just as vain as the other way around. Like there's some very narrow sweet spot where it's okay to be attracted to someone.
Not only that (attraction is a thing after all) but saying "I don't get why people would want to be with someone's wit x body type" directly correlates the validity of a relationship to the partners' appearance.
I'm not attracted to chubby or skinny girls. My first girlfriend was skinny, my last was chubby. I couldn't really give a fuck about their frame because that's not what made them beautiful in my eyes, and they were attractive to me because I wanted to love/fuck them, their body wasn't a prop with which I had sex.
It's totally okay to have preferences. I prefer fit brunettes with an attitude. That doesn't invalidates the beauty of all the rest of humanity, and that doesn't even mean I should build my relationships on that very narrow standart. And other people's health and body image isn't any of my business.
And personally I'm getting a bit tired of people treating Beauty like there's some absolute gauge to it. Same with "fat", "skinny", etc.
Harry up there thinks Amy Shumer is fat. She's fat to him. It's okay if he thinks so, who the hell cares. As long as he doesn't invalidates her actions and rights for it, I have no problems with that.
When I have to go downtown I go there on foot. For some people it's far, they will tell me how far they think it is and I'll disagree. That shit is all relative, you can compare BMI all you want all day long, to some people I'm a walking miniature skeleton, to some others I should be a model (hi mom !).
Sidenote, I find Beyonce absolutely dashing. And Amy Shumer's photos were beautiful.