If your theory is correct, then why would they also keep many of their users uninformed? Referring to Lemmy.ml, of course. You claim it’s for legitimacy, but doesn’t that cease to fulfill its purpose?
Because the users that don't know what the instance is for are the ones that help lend legitimacy to it, because then people like you can believe that it's just a general instance with no political undertones. You aren't running cover for them, you are their cover.
Just think for a second about what you're suggesting. They want to make an instance that is to lend legitimacy to a fringe political ideology, and they openly tell all of their users that that's exactly what they're doing? Then all anyone would need to do to destroy that legitimacy would be to publish whatever message the users receive explaining the true purpose of the instance. The cover only works if it's deniable, and your idea would make it completely undeniable.
Is the goal to make a generalist instance, but with slightly more MLs, but also divert the MLs to Lemmygrad?