Ok — I suppose, to break it down, shaming only works if you’re dealing with your peers.
The problem with the soccer players, is that they went along with the kid, which wasn’t the right response because it just perpetuated racism. However, to get angry at the kid in some way or to “force” him to stand in front of the black player I think would also not be correct, because the adults would just be seen as “mean adults.”
The soccer players, I think, should have said “I will not allow a photograph of myself to be taken under these conditions.” I will not allow myself to be photographed, I will not allow myself to be used to perpetuate racism. If that happened, then the other children may have pressured the racist child to cooperate, and they may have been effective as his peer. But, the adults were unlikely to be able to change behavior directly, so they should have used another tactic.
In the larger context: liberals shaming of conservatives is ineffective. However, conservatives shaming other conservatives is very effective in changing their behavior. The one thing that got Yiannopoulos to ever apologize for anything was his conservative book publisher dropping his book contract.
Anyway, thanks for the question. I think that was a gap in my understanding, you helped me flesh it out. So, social shaming only works within your own group. If you’re dealing with an “in-group” member, I guess tying anti-racism to social capital is good. If you’re dealing with an “out-group” member, it will be ineffective, and you’ll need a new strategy.