I understand that, but no amount of encouragement is going to get everyone to run a personal relay, no matter how easy it is. At least not anytime soon. Half of the current die-hard users barely know what relays really do... And we often don't know now, what we might need later, especially when it comes to aggression that elevates slowly over time.
There seems to be plently of qualms with the way Primal chooses to operate, how they handle delete requests being among them. I don't see any of those things as a broader nostr problem, though. Right now, using Primal might be one of the easiest ways to gather notes in those adverse situations, should something like that arise.
I agree that all relays ought to have those types of policies, clearly stated and easily accessible to users, too, so that users can know where to search if they need something, where/how to publish in order to best maintain control of their exposure, when to expect their data to vanish, etc. I just view the stickiness as a cloaked benefit, is all. I know a lot of people won't see it that way, at least until they have a need.