At this point I'm fairly confident this is not about the technology per se, so it's pointless to try and find differences and similarities and make sense of them. It's about politics, it's about personalities, impressions and incentives. I feel like governments just gave up on pretending that laws matter, now it's all about "indicting a ham sandwich".

Meaning, Signal is "in the clear" right now, because nobody fucking cares. It might not be, should the owner change, or should it became more popular (either in general or among certain categories of people).