Doesn't matter if he's going for the ball, otherwise the rule would require him stop and basically let the dude catch it
I love when announcers go all in explaining why a penalty was called and then have to backtrack immediately when the flag is picked up
So, on that play I agree they made the right call (though it was close)...but if you obliterate a WR from behind going for the ball, its 100% pass interference. You have to make the effort to reach around him to get the ball (which Ward did), and then if you hit the WRs back in the process its ok