CEX deserves all the hates it getting now but doesn't mean it has also not been helpful to bitcoin and crypto space.
CEX will always be there and will help us buy and sell not only Bitcoin but all of the cryptocurrency the particular exchange has been listed.What happened to FTX did have a contagion effect not only to CEX but all of the companies and projects that has a connection with FTX. CEX being criticized is pretty normal already especially with the exchange this huge will turn out to be a fraud exchange. Investors can hate the CEX as well but that is temporary only and in the end, most who are hating those CEX are the ones who will use them as well. Where they will buy crypto if they wanted to? DEX probably but you can't buy Bitcoin on DEX'es right?
After the whole issues of FTX my advice is though buying from CEX is safer but storing all your funds there should be avoided and for holders just stick with DEX.
It's the same as "Don't store your coins in a CEX" that's all. 
Even though we are saying this all the time, there are still investors who still prefer storing their coins in an exchanges. Maybe they have a personal reason why they are doing it, but it's riskier than just storing it on your own wallet that you have the private keys.