This is correct but the All Writs Act can compel third parties to help in a criminal investigation, like a phone company being asked to help wiretap a phone. Signal by design at the most would have only contacts that you shared and IP address/access log. Apple was able to argue that they shouldn’t be forced to push an update to unlock the phone of that terrorist in California so there are limits to it but they are not entirely clear.
Idea that Apple would not add backdoors privately regardless of what actions they take publicly is a stretch give Apple has obviously been more than happy to tailor their systems to China’s demands. Core difference between China and US is that US is fine on government spying on it as long as it’s done in secrecy.
