Those people don't have the knowledge of bitcoin because bitcoin isn't a coin for staking since it uses POW and not POS. Secondly, how much profits will you generate for staking your coins, it means that you are gambling with your investment. If your bitcoin is in your self custody wallet as the price increases, you see your profit.
Well, they don't care about POW, POS, POA, POH etc.
I don't know how much the profit from staking, let's say 4%.
If you hold in self custody wallet, your 1 BTC when the price was $20,000, now your 1 BTC worth $40,000. You earn $20,000.
If they stake in centralized exchange, their 1 BTC when the price was $20,000, now their BTC would be 1.04 BTC, they earn $21,600. Profit is profit.
Currently, bitcoin transaction fee is very cheap as you can pay below 1sat/Vbyte for sending funds. I know that you cannot trade without an exchange which is the reason why only traders should keep their trading funds in the exchange.
Your funds can be freezed by exchange if the government is investigating you.
It's not about cheap, if you hold in self custody wallet, you will spend more money and not maximizing your profit.
For now they don't have any problem with CEX, so they don't care about freeze funds.