Pretty sure it's the former, since the above is a way to ensure that Cellebrite can't just gather all implied exploit files and make sure they've got those specific problems all patched. This is, quite literally, an informational attempt at guerilla/asymmetric warfare, where Signal is trying to make engaging with them too costly, while also making a few blows quite a bit above their weight level. Cellebrite now has to decide whether to keep after this adversary that both is hard to pin down, ambushes them, and has shown it can hit them really hard where it matters (credibility, and thus their pocket book).
I think this taints any phone having Signal installed.
Now imagine if Hack Back laws actually passed... companies like Whisper Systems would have had impunity for even more shenanigans :)