Well, I think that's kind of a strange and cynical interpretation of all this.
The suggestion that he didn't "sacrifice" that much simply because he's rich is just being pointlessly nitpicky and also missing the broader significance. Kaepernick is black, and no amount of money can completely shield him from the consequences of being a black man in a racist society. He publicly showed solidarity for murder victims and now he can't play the game. That's because he's a black dude caring about an important black issue, which is apparently not allowed in the NFL. So his money and his status couldn't protect him from the consequences of rocking the boat. Those consequences may not be as dire as kids getting gunned down in the street, obviously, but it shows how the racial hierarchy of America always remains intact, even for millionaires.
The whole reason he was blackballed from the NFL was to shut him up and also to inspire fear in any other NFL players who might want to protest police brutality. It sends a message: go down this path and watch your career disappear. It's a concerted effort to punish Kaepernick and to intimidate everyone else. It creates an stifling atmosphere where, even if someone privately sympathizes with BLM, a lot of people probably won't take the risk because of what it might cost him. That's all intentional. So for Kaepernick to stand by his actions and for Nike to back him up like this is an attempt to fight back against that kind of silencing effect. Our society is filled with powerful people who refuse to do the right thing because they're afraid for their career, which is why something like this truly does require a certain degree of political and moral conviction that outshines the desire to preserve ones career. So I would argue that this absolutely does qualify as a "sacrifice" (also want to point out that the dude has received numerous death threats for what he did), and that it's not remotely tone deaf for Nike to describe it as such.
And obviously these are all just symbolic gestures, because that's the inherent nature of mass pop culture. That's what art is. When it comes to celebrities, artists, famous athletes, etc, we are always talking about the realm of the symbolic.