well you and ravenmadness have certainly morphed the contention from "you can't hit the head with the shoulder" to "you can't intentionally try to injure a player / can't hit a defenseless player."
anyway I know you know football tank. the hoyer hit for example was shoulder to head with no flag. pretty much puts it all to rest.
the defenseless player rule was put into effect for a couple situatiojns, like a wide receiver with his back turned to a guy like jack tatum barreling in full bore on an overthrown ball and lining a guy up with no chance to evade the blow.
now regarding the qb the defensive player / qb rule applies to a qb so engrossed looking downfield he can't avoid a head or knee shot. in that case you certainly can't lay a shoulder to the head of a concentrating qb in the pocket.
those are the rules.
however, (listen close ravenrabies), when a qb becomes a runner and is charging the mark to gain, all rules are off and the only thing to protect him is a timely slide. but when he pushes it too far he loses the benefit of the doubt and WHAM. concussion protocol baby!
for those that still want to argue that joejoe slid in time, its the same bunch that think he's sharp in the pocket to. Every see brady obliterated like that? no cuz he and Rodgers have the awareness to pull up. joe don't. anyways the baseball fans here will certainly know a proper and timely slide takes the head out of harms way.