The table is quite big (190+ lines of hand-written HTML) and it doesn’t fit on mobile phone screens unless you zoom out. It should be fine on desktop. It also specifies the criteria followed and has analysis of some of the IMs in the table (not close to all of them, I hope to add more analysis in the future).
Counter-arguments are always welcome. Sources and additional information too. Note that the typical privacy recommendation (Signal) is not recommended here. It does not meet our criteria, being centralized and requiring a phone number. I don’t want to hate on Signal since it’s doing a decent job spreading the importance of E2EE, however we can not recommend it for the given reasons.
Syncing between clients is still possible, although it may not be implemented. There’s no reason why a P2P client that’s part of a conversation can’t request past messages from any other client that’s part of that conversation. All P2P does is move the data handling to the edge.
This is what I was implying: if a chat design doesn’t account for this, it’s IMHO not a good useful design - especially in the case that the design also leaks some metadata, and so isn’t 100% targetted at dissidents.
P.s. I’m going to write my own chat application, with blackjack, and hookers.