That means that devs can't fix that or they actually did that in a purpose? it's hard to trust defi project these days. A normal investor won't have this type of knowledge that you have shared.
This is like the devs taking advantage of the majority.
There are two possibilities which are bug on code logic or purposefully do that for rug pull. indeed it is hard to trust DeFi project these days because the community is not well knowledged yet in that area unlike blockchain itself. a lot of rug pulling happened due to lack of knowledge from the investor and the community in how smart contract logic works, if we are somehow know how it is going to work. we should be able to prevent any rug pull from the developer and we can prevent any exploit that might happen.
DeFi is not mature yet, that is why it is a golden land for scammer to make many quick.