I said that the defensive player endangered himself by not seeing what he was hitting. That's how guys break their necks. I don't agree with kicking someone out of a game for doing something that is stupid for himself. I can live with a 15 yard penalty there, just not an ejection. Punishment doesn't fit the crime.
Not sure where the "tougher back in their day" stuff is coming from. I am not and would not try to make that point. Players are bigger, stronger, faster, more skilled and better technicians than they've ever been. By far. With that, though, I would say that the speed of the game sometimes makes certain types of incidental contact unavoidable when guys on both sides are playing aggressively, twisting, turning and diving. Sometimes sh!t happens and guys are going to hit their heads together or someone's going to hit someone really hard when the guy wasn't ready for it or someone's head is going to make first contact. I think some of that has to be let go or at the very least not result in ejections.