This is truly a hacker’s retort. It attacks Cellebrite's ability to operate by casting doubt on the reports generated by the product that their customers may wish to use in court. It places them in legal peril from Apple, and removes any cover Apple would have to not take legal action. (I assume someone at Apple knew they were shipping their DLLs?) It makes a thinly-veiled threat that any random Signal user's data ma…
I really seriously doubt that anyone would ever advance the idea that Signal had deliberately framed them by creating false data on their phone. I don't see this as much more than pointing out that Cellebrite has vulnerabilities, just like the ones they exploit.
You wouldn't imply that Signal had framed you. You would imply that someone else had framed you using the same vulnerabilities as Signal has now indicated exists. i.e. You can't trust Cellebrite because it's now known to be trivial to subvert their software. It's also difficult for Cellebrite to prove that there aren't remaining vulnerabilities in their software since Signal didn't disclose the problems they found and won't do so unless Cellebrite discloses the exploits they claim to be using in Signal.