I prefer to look at the inverse - where is the dumb money going, so I can limit my exposure to it?
A lot of dumb money is going into real estate, crypto, TSLA, and pre-earnings stocks. There are plenty of pre-earnings stocks that will be great companies no doubt, but Amazon's success story has created in my opinion a bit of a celebrity effect - where even though there can only be 1 Michael Jordan, there are hundreds of thousands of kids convinced they will be the next Michael Jordan. But instead there are 100,000 investors convinced that Square will be the next 10 bagger.
I would never short dumb money investments, because the cult like belief of the longs can quite easily outlast my position. What these investments lack in intrinsic value creation they can make up for in cash inflows from foolish investors.
So rather than be long or short, I'd rather just have nothing to do with them. You could argue there is decent evidence of dumb money in the overall stock market based on historical shiller PE averages, which says the stock market is quite expensive right now... but you could also argue the stock market isn't expensive, capital is cheap.
And indeed it is, artificially so, which would mean that perhaps our stock market is in turn artificially expensive. So it's understandable that we would scour the market for stocks that are a relatively good deal.