The feature was not bad when it was first introduced, but I don't know how it fares against brigading and more targeted psyops by bigger actors.

Also are we absolutely sure that community notes have immunity from moderators and they're not manipulated in any way?

Community notes are indeed a good feature at first blush, but considering the current climate of "freedom of speech / post-truth / let's move fast and break society norms", it's more dangerous than a group of allegedly biased fact checkers.

It's a way of deregulating the social media platforms to level of utilities which carry whatever passes through them without prejudice, and shifting blame to the people for believing what they read.

The thing they're designing is very ripe for manipulating people en masse.