Right side charging is mandatory in long distance shooting. The off hand is trapped by a sling and shooting jacket, the trigger hand free to move around.
It's not all about carbine use.
I don't dispute the left side charger being faster in combat use when you need to charge the weapon. The fly in the ointment of that concept is that the AR15 design already has the answer - the bolt hold open. When the last round is fired, the bolt hold open is pushed up by the magazine follower and you trade out the empty mag for a full one.
You don't need to charge anything. Just pop the hold open to release the bolt.
This is why the M16 in all it's variants hasn't needed ANY improved charging handle for combat use in 45 years. I started my career as a soldier in the 1970's being trained on a slick side M16 (A - nothing) while owning a HK91, I can say that left side charging isn't all that. I prefer the bolt hold open and not charging at all. It has rarely failed me, and everytime I joggled it to chamber the bolt too early, I was in a rush and needed to calm down.
The original M16 had a hook charging trigger in the upper sight handle, even more ambidextrous than the rear charger. I still wonder why we didn't retain it - you don't have to move your head at all to charge it. Another change by Colt to satisfy a Garand command climate.
Really all very moot, there are no zombies, there is no revolution, we aren't in the streets. It's a recreational gun for the most part, take it to the range or hunting and enjoy.