I'm I wrong here, or is this translated exactly the opposite of what it means (and the same as Mahoro's original phrase)?

Or is that big old square zero somehow used to negate the meaning?

えっちなのはいけないと思い is what she's saying.

That's how I read it. It's in conflict with her character and gesture, but that's what it means.

Yoshika has to say her cosplay character's quote, even if it's exactly opposite to her mindset, I guess.