I think it's dumb (bad idea), but not crazy (insane or illogical).
There is always someone who thinks the market is about to crash. We need those people to keep the market in balance, to drive down equity prices so that I can buy future earnings at reasonable current prices. I can't make a profit in the market if everyone thinks the economy will continue to grow, because there would be no more risk arbitrage.
So, I wholeheartedly encourage you to make bad market decisions. Please bet against the previously unstoppable force of American capitalism. Plan for widespread economic collapse. Sell me your stocks at a discount, and buy gold instead. Every once in a while your plan will be profitable (assuming you buy back in after the drop), but most of the time people on your plan will only help people like me get richer and richer.
Do you think you've identified a coming collapse before everyone else? If yes, you are a genius and about to be rich. If no, you are about to forfeit future profits to me and the rest of the buy and holders.