I mean, the post says it'll show you who your enemies are, and that's absolutely correct. It just doesn't mention that if your manager is one of those enemies, then following this advice will hand them all they need to throw you under the bus.

To be fair it's very useful to know if your manager is that sort, and if they are then you should probably leave if at all able, but it's better to find out quietly and then jump rather than being pushed.