Also worth noting is that there are already special, aggravated charges for crimes that involve cops, and they're enforced far more strictly. Shove someone once at a bar and you might technically be guilty of some minor assault charge, but odds are good you won't get any charges out of that, or you can plead down to something even smaller. But shove a cop once? Even if it's while they're roughing you up? You'll get the book thrown at you.