The growing presence of encrypted communications apps makes a lot of communities safer and stronger. But the possibility of physical device seizure and government coercion is growing as well, which is why every such app should have some kind of self-destruct mode to protect its user and their contacts.
End to end encryption like that you see in Signal and (if you opt into it) WhatsApp is great at preventing governments and other malicious actors from accessing your messages while they are in transit. But as with nearly all cybersecurity matters, physical access to either device or user or both changes things considerably.
For example, take this Hong Kong citizen who was forced to unlock their phone and reveal their followers and other messaging data to police. It’s one thing to do this with a court order to see if, say, a person was secretly cyberstalking someone in violation of a restraining order. It’s quite another to use as a dragnet for political dissidents.