Yeah, I had to do a double take when I saw Signal included in that sentence.
I value privacy & security personally, and want Signal to succeed, but any compromise to UX in the name of privacy & security is going to make it impossible for Signal to compete as a mainstream messaging platform where network effects are paramount.
True, but if you're just using phone and desktop, Signal works well.
My point here isn't that Signal is perfect, just that the implementations by Signal and others shows that support for e2ee DMs on multiple devices is solvable. Teams can decide what their users need and how much flexibility is worth supporting. A public company of Twitter's size is clearly capable of solving this for some broad set of use cases.
