I think it is also to inform the rookies, that there is a standard to uphold. Not just team-wise, but NFL-wise as well.
Coach Tomlin gives them that 1" speech. Fighting for your brothers, fighting for all those who disrespect you, fighting for that last inch..............
They also instill into them that during interviews they need to say "I just want to play for Coach Tomlin".
So as you can see, it is a little more complicated than just showing up.
Yes, a "darling" is born unto us.
Salute the nation