Pretty sure parents and coaches do this all the time without getting punched. You guys might not like Smith, but he is the starting quarterback and is a guy who might need to get in a teammate's face every now and then. If this guy can't handle that, he's in the wrong line of work.
I don't know, when I played, that would fly if the quarterback was balling out an offensive lineman or running back, but the offensive players don't ball out defensive players or vice versa. You let the leader of that group take care of that.
As ridiculous as that sounds, on a lot of football teams, the offense and defense don't interact a whole lot, and a defensive player isn't going to respect a quarterback a whole lot unless it's somone like a Manning, Brady or Rodgers.