Celcius is not decentralized, it is not a community led-project, it is not free/open source software.
So who is "they"? It's obvious to me that the type of person who endorses something like celcius just sees cryptocurrency as a free money machine, and does not actually have real princples regarding decentralization and whatnot.
Cryptocurrency can be strong against censorship etc. But it is clearly not sufficient in itself for censorship resistance etc (e.g. what value is being secured? from who? how?) It is analagous to saying that encryption is good for security but the presence of encryption is not sufficient for security (e.g. what data is being secured? from who? how?).
The fact that celcius can steal your deposit despite the fact that cryptocurrency is involved is analagous to the fact that GMail can read your emails despite the fact that HTTPS is involved.
The issue is people keep reinventing centralized banking on top of it. Exchanges for example are actually just banks in disguise. Of course reinventing centralized banks brings forth all the problems associated with centralized banking. Problems society has already identified and remedied. All the drawbacks and none of the benefits.
The solution is of course to stop reinventing banks and start using cryptocurrency like it was meant to be used: as a currency.