I find some of the responses in this thread pretty disheartening tbh.
It's not in teams or players' interest to retire from the field with a concussion. I'd have thought that was pretty obvious. For every player who puts his brain health absolutely paramount, there are a number of guys who want to get back in the game, who worry about how the team would view them if they pull out, who don't want concussions to damage their contract value.
So, just like the ref in a boxing match has to tell a fighter he can't continue even when he wants to, somebody external has to tell a NFL player he can't go back on the field.
Unfortunately in the NFL, the guy who makes that call is the Designated Team Physician, not the independent Neuro counsel, who performs the tests with various team personnel present.
You can see the opportunity for bias.
I'm sure the protocol was followed. But the protocol itself is a pretty wishy-washy business, partly as it's designed that way and partly because concussion is v hard to detect medically. It can be easily cheated/manipulated by the player and - fundamentally - at the end the team doctor decides.
If people still believe Tua had a bad back which miraculously cleared up to let him back in unhindered, then fine. If people want to support their team and QB to the point that they just want him on the field regardless and they believe whatever argument supports that happening, then fine.
But please don't question the bona fides of those of us who are concerned about brain injury in contact sports like Am Football and pro rugby. If it's not handled properly, then lawsuits and protective parents will ensure these sports just die out.