What does beattys speech about Clarisse reveal about him? Why does he speak so passionately?

Here is the quote,

Beatty smiled. "Here or there, that's bound to occur. Clarisse McClellan? We've a record on her family. We've watched them carefully. Heredity and environment are funny things. You can't rid yourselves of all the odd ducks in just a few years. The home environment can undo a lot you try to do at school. That's why we've lowered the kindergarten age year after year until now we're almost snatching them from the cradle. We had some false alarms on the McClellans, when they lived in Chicago. Never found a book. Uncle had a mixed record; antisocial. The girl? She was a time bomb. The family had been feeding her subconscious, I'm sure, from what I saw of her school record. She didn't want to know how a thing was done, but why. That can be embarrassing. You ask Why to a lot of things and you wind up very unhappy indeed, if you keep at it. The poor girl's better off dead."

"Yes, dead."

Beatty is passionate in that he dismisses Clarisse and her family as "odd" and counter to what is "normal" thinking. Beatty is in fact very intelligent. He understands the other side, the side of knowledge and depth. Beatty just chooses to dismiss it; he is too entrenched in the official ideology.