As I said, it is possible and possible in a decentralised way, but these search plugins depend on search indexes (unless there is a black magic that breaks my understanding of the world), and these are just as vulnerable to censorship as any service provider.

Things get way worse when your search requirements are real-time microblogging feeds and their low latency interactions.

The best way to achieve censorship resistance is to focus on use cases that lends themselves well to that. Torrent indexes and indexing archived resources are definitely one of the best use cases.