It's an unfortunate part of the game.
If players are leading with their head it's going to happen.
It's a fundamental flaw in coaching. Guys aren't taught how to tackle from the beginning (whatever level they start out) and it snowballs into leading with the head.
Some of it, too, is the player's physical abilities (strength, how hard they hit, etc) have grown
alot greater and much faster than the safety equipment has or might even be able to;
the rate at which players are these reaching higher peaks of physical performance we all see and enjoy now has increased drastically, unfortunately, compared to the improvements in the equipment. The modern helmet still does a pretty good job protecting the head, but it's nowhere near as fully protective or effective as it used to be.
The number of concussions has really risen in the last 10 years or so, to the point - there were at least 3 alone in the NFL in week 1, and that was only looking at 2 games - where it's not just something those in charge of the game can just ignore anymore (especially after multiple reported incidents of ex-players experiencing head-trauma induced depression later in life and that ex-nfl lineman killing himself 7 or 8 years back or so).
Unfortunately though, they're really at this point playing with pretty out-dated equipment. The helmet needs to be improved so that anytime a player takes a big helmet hit, he doesn't fall limp to the ground and have to be carried off on a cart or taken to a hospital.
Player safety has always been a huge part of the game ever since back when Theodore Roosevelt made them reevaluate/improve the sport after the 1905 season caused 18 deaths. It's a dangerous sport, they're trying to find some ways to keep these kids from ending up with serious problems
But rules like these coming up now are really about protecting the players. With all the findings coming in the last few years of the mild to severe brain damage later in life that's showing up from concussions, they're not really an injury anymore that can be brushed off as 'part of the game,' both on a moral level for the actual physical and mental well being of these kids, but in some ways a legal perspective as well. Until someone's able to come up with a way to drastically improve the helmet's protection, the closest thing they can currently do are penalties to try to discourage behaviors that might lead to players causing them, unfortunately.
I do agree that the tackle methods need to be taught better by coaches so things like this won't happen, but it's also alot how the modern helmet unfortunately no longer protects as effectively it really needs to be for the modern game.