Yes. DMs on Twitter are Direct Messages and are supposed to be private messages send to someone else that no one else can see (except server admins, et al, as we are talking about here). If you send a DM to someone on Twitter or whatever social media (they use DMs to mean private messages on Instagram as well) it’s not on the public feed, no one can search it. Like having a text message conversation
@TiffyBelle
@Bloonface
And if other instance owners have access to the private messages of people on every instance, that is a shockingly large flaw. I’m not exactly sure how insecure private messaging would be here. Not that I have people to message. But it being centralized would be more secure if decentralization would allow a much larger number of people to have access to something that, really, should be private.
There are an overwhelming number of people I don’t think are savvy or cynical enough, call it what you will, to understand that just because they call something a private message - or just because it’s supposed to be a one to one interaction - doesn’t mean no one else can see it. I would think, if anything, an overwhelming majority of people who send a private message/DM on a social media assume that no one else at ALL has access to that information.