Does size stop you from wearing certain clothes?

Today at the train station there was a girl there (she couldn't be anymore than a size 16) and she was wearing cut off denim shorts, the type that shows a bit of the bum. She obviously was wearing tights and I didn't think anything of it but two boys were speaking to each other and said "that's disgusting" and it made me think, does being a certain size actually stop you from wearing certain stuff or not?

Ok, I have to admit I am guilty of thinking things like "she shouldn't be wearing that" but who doesn't? But the thing I'm thinking of is, should curvy or plus sized women stick to always being covered up? Do slim or size zero girls actually have the body to be wearing tight clothing and cropped tops?

I'd like to know peoples opinions on this because to me I feel as if as long as you have the confidence and personality to wear something it looks amazing, no matter the size of the person.