[Q] Oracle dilemma

What's the oracle dilemma?

And how it's related to Ethereum?

I understand the oracle is like chainlink and how they get out of the chain data to Blockchain. And it's used mostly for defi.

I have been listening from bitcoiners that it's one of the negative things of Ethereum ecosystem and one of the centralized issue of Ethereum. They are trying to imply it's one of the on chain solution that Ethereum provided (like an eip) but I know it's not.

I believe it's not related to Ethereum protocol directly and it should an issue (more of challenge that needs an innovation solutions) for app layer protocols directly.

So why a lot of negativity?