I never saw Cho acting in the spiteful, hurtful way that Ginny did. Nor did Cho behave like a poor sport when playing Quidditch.

I think that nearly EVERY student (among the main and secondary characters) in book six acted like a jerk. Luna and Neville seemed to be the only ones behaving themselves. Hmmm...neither of them got "paired-up" either. Did they escape JKR's teen hormone rampage? ;)