I'm always wary of claims of type "if we do otherwise moral thing X someone else may react by committing horrific crime Y, so we should not do X"; at the least we should be very explicit about where moral blame lies, and at the most we should discount Y because of game-theoretical incentives (example: not paying off kidnappers). Still, it seems like this doesn't much affect Eliezer's point here.

By the way, I'm always nervous about persuading people of impopular political positions when I agree with them on far more important non-political issues; they'll probably lose social standing.