No, basically you are right. You’ll be left with cryptographic proof of all the shitposts you made in the past 😄.

As long as timestamps on notes can be backdated as far back as you want, you could simply leak your nostr private key at a later stage and then argue, that a specific post from the past was not made by you, but by an imposter who took your (now public) nsec and backdated a particularly nasty note, that you would never have posted yourself. 😉