Perhaps you read something that I missed then. In his OP he states his reasoning is because of the "quantity" of coins, not the "quality." Personally I see no reason to attack coins, especially ones that meet his own agenda and not the consensus of the entire crypto community. History has shown that most all shit coins will die natural deaths anyway. Let the herd cull itself instead of having some wannabe savior of the crypto world launch attacks on whatever coins he chooses.
The whole point of crypto-coins is that they are safe from doublespend. If someone shows that they aren't, then he is doing a service to the cryptocurrency industry.
Crypto is still in early days. We are building bridges, and it's better for someone to stress test the bridges before they are declared safe for the general population. If these bridges are unsafe, I want to know now (even if I lose some money).
You'll notice that many who are invested in PoS coins want attacks to be attempted. Better it happen out in the open now rather than in secret in the future.
Also, his attacks don't seem to be destroying coins, just showing they aren't safe. No reason coins couldn't shore up their defenses after the attack, and come back stronger.