It's activist art depicting a scene of a non-historical event. While I get what the mural is trying to say, I don't necessarily think that this is something that kids should have to see every day when they're not in the context of a history class.

Think about it; how would you feel going to work every day if your office had murals of holocaust victims being sent into gas chambers? There's as valid a lesson to be learned from such a mural, but it's unnecessarily disturbing because it's out of context.

So no, the actual motive of San Francisco officials aside, I don't think it's appropriate for a high school mural.