Yeah. It’s useful as a rule of thumb for who you should probably be extra careful not to mock for no good reason, but satire falls into the category of legitimate criticism layered in humor. Nobody should be immune to legitimate criticism, and nobody should be mocked for no good reason, so as a rule it’s only useful when you’re already failing to follow other, more important rules.
I don’t think the idea of calculating punch vectors — i.e., trying to figure out power relationships — is not worthwhile, though. Systematic inequality tends to be easy to ignore, so encouraging people to look for it is important. But the thing about legitimate criticism is that it’s not an attack: the target of criticism benefits from understanding and accepting it, by definition. In other words, calculating power relationships should probably not be a part of determining who to criticize (although it may be part of determining how to criticize them), because criticism is a positive-sum game.