I think I'd even generalize further and follow theymos' advice not to keep money in
online accounts. The emphasis there is
online accounts. So this is not just about centralized exchanges. This is about any platform that keeps your money. So this covers the likes of FTX, 3AC, Celsius, Voyager, BlockFi, and others. They all went awry. Again, what we need to avoid are not just exchanges but also hedge fund sites, investment platforms offering unsustainably high yields, fake DeFi apps, crypto lending companies, and the rest.
However, your conclusion is not precisely correct.
So I am led to the conclusion that, cryptocurrency is not the problem...
To a certain extent, they are also the problem. Terra (LUNA) is a cryptocurrency. Solana (SOL) is a cryptocurrency. They are a problem. So while there is always a human factor that causes problems-- the tendency to buy their coins, for example, hoping that they will grow in price-- there is also the fact that
cryptocurrencies nowadays are mostly faulty or outright scams.
This is probably the reason why
Bitcoin, not crypto somewhat became a battle cry for some Bitcoin supporters.