You're actually right! That's why, after closing zkSNACKS' coordinator, it might take some time before another coordinator will gain enough reputation for it to gain enough trust from the community, and therefore gain the liquidity to give an efficient and secure service.
You don't have to trust coordinators, there's no reputation required.
I'm curious about new coordinators, they do need to bootstrap the service with their own liquidity, no?
No. Coinjoins are made of user inputs.
But if a coordinator doesn't accumulate enough liquidity, then like you posted, it would be less secure, inefficient, and therefore a less effective way to CoinJoin outputs.
Plus, I know the liquidity pool is supposed to be made of user inputs, but if not many users actually want to use the coordinator, then there should probably be a bootstrapping process during the start, no?