CEX and DEX can both have hacks. An open source DEX can be verified, formally tested, and made immutable and un-upgradable on chain, like Uniswap.
Uniswap V2 contract is 2 years unchanged, $3.8B TVL and $1B daily volume, close to 10 year old Coinbase CEX. Not bad for being a joke.
I'd rather gamble with Uniswap protocol risk than FTX human fraud and greed risk.
Hardly says that DeFi as a category is reliable.
You said "day traders on FTX are learning first hand the value of DeFi", but DeFi is just as much of a shitshow as the rest and has had just as many collapses.
I am one of these people: I had funds locked into a CEX, was lucky to pull them out some days before turmoil but others not so lucky. During that time my DeFi holdings were fine. I would now rather take on protocol risk of something established and proven like Uniswap, instead of risking with an unregulated CEX.