Not if it destroys the credibility of a rival coin, which I suspect could be the case here. Many in the "real Bitcoin" community call Bitcoin Cash a fraud because its existence reveals the specious value of their "real" cryptocurrency.

Executing a double spend attack on Bitcoin Cash would be a massive success for Bitcoin owners. Same goes for Bitcoin Gold.

You could even create a mining pool/network - let's call it CoinFucker - where every now and then the pool's resources were diverted to attack a rival coin. Doing so damages that coin's reputation, and in doing so reduces the competition. This would be a great way for the majority of mining/computational power to squash would-be rivals.