Sealioning is the discussion equivalent of a DoS (denial of service) attack. In both, the content of the reply is irrelevant; the goal is to flood the person/machine with multiple requests, until they reach a limit and stop dropping the requests altogether.

And while the concept has some problems because it handles some esoteric babble called "intentions" (see: "goal"), it's still useful when you focus on the behaviour instead.

Funnily enough saying someone is sealioning falls within the passive-aggressive behaviour you seem to despise so much.

Pass-aggro is about tone, not content. You can state something like "you're sealioning" in a passive aggressive way, or a rude way, or under a bald-on record, so goes on.