Why are they embarrassed?

"Look, her face is turning pink!" One of the aliens pointed out. "What does that mean?"

"That is very interesting," The Collector droned. "You see, some such responses to shame or humiliation."

"But why is this creature ashamed?"

"There are many things that shame these Kyrptonians." The Collector said. "Though, such mammals pride themselves on the size of their reproductive organs. It may be because her breasts are not yet developed."

"HEY!" Kara yelped. Okay, she didn't have huge tits like Wonder Woman. It didn't mean she wasn't developed!

"Or, it may be because she has no fur over her crotch." The collector pointed to her barely covered crotch.

"Hey, I shaved that!" Kara pointed out. The aliens kept talking about her as though she couldn't understand.