Definitely agree, I've just considered reduced deletability closer to a bug than a feature, but I'm also open to thinking about it differently. To steelman your point, extremely prominent figures not being able to delete their posts increases their accountability, like Bitcoin's reduced privacy increases institution's transparency, despite the ideal end state of the technology being perfect deletibilty / privacy.
Discussion
we live in a world where a single truth social post by the president of the united states can send global markets up or down significantly, or worse, start a war
we are also in a world that will be dominated by deep fakes
it is insane that we trust centralized corporate entities to provide (weak) authenticity and availability guarantees