For the record, I am completely against screaming.

You see, screaming happens on a spectrum. It really isn't black and white. I wish there was a quantitative scale, but there isn't. And it actually does depend on a person's natural demeanor, some people literally scream when they're even being nice or happy! Is raising your voice without being negative called "screaming". I don't think so.

Perhaps true "screaming" is that which is coupled with negative words / profanity / putting someone down.