This is a a business operating to target children to deliver them content they know is inappropriate for them.

This behaviour is predatory. It shouldn’t be tolerated against children. The content is promoted for children, so it’s reasonable for a parent to assume the content is appropriate for them.

Maintaining and testing such an app has costs and risks. They may think it’s more secure that signal does this. It is also harder to attack all of signal.

They are also significantly resource constrained, everything they have goes towards defence. The effort building the app could be deployed on developing weapon systems they can’t buy.

Your right nations should have their own independent systems for secure communications for military, politicians and civil service.