You have never coached (I am guessing) or played. That is not a knock, it is just what it seems like.
No joke but one of the biggest things that is stressed by coaches is body language and attitude. You should see HS film and how college coaches critique it when a kid IS NOT positive.
Most teams are made up of guys that are excited and happy and energetic.
Pointing, head down, shoulders slumped and going slow after a play = kiss of death. You won't get recruited and/or you won't play.
Every coach in the country will tell you it is much easier to get a kid to tone it done as opposed to getting a kid to amp it up and lose bad body language. That shit is a team cancer.
Also, if you want to know what most DB's are saying after a catch...it is this..."Nice catch baby, that will be the last one" and/or "Nice catch 82, don't expect anymore". If that is what you consider taunting, well, you are pretty soft.
I have coached like 10 guys that went on to D1. College coaches never brought up the stuff you seem to think is a detriment, but they always bring up bad body language, always.