Shorting the market is a sensible strategy if valuations are as detached from fundamentals and reality as he says they are, so shorting isn’t gambling in every case.
Aside: I also fundamentally disagree with you, I think shorting is never a good idea, nor is participating any type of market game a good idea. These market games are a rigged game where the owners of capital engage in systematic exploitation of the working classes. Everyone who makes money by gaming the market made it because hundreds of worker did not get their fair share for their work.
It sounds like participation in markets isn’t right for you so don’t do it.