Earlier quoted context omitted.
I've seen a growing number of anti-Signal posts and activism lately, mostly surrounding the (well-documented) design tradeoffs that Signal makes for usability and privacy (such as opting to use phone numbers for usernames, to avoid having to store contact lists/social graphs on Signal servers), or their famous decision not to federate/interoperate. Perhaps it's just criticism growing in lockstep with Signal's overall…
One major reason for the push back against Signal promotion is that it does not represent any sort of federated protocol. It is a complete silo. So if it did become popular it would eventually be a serious problem and would need to be fought against.
It already is.