It is a combination of their previous behavior plus the behavior of the various agencies.

For example: https://www.theguardian.com/australia-news/2020/apr/23/gover...

The fact that law enforcement even asked for this would be to many people completely unacceptable.

It's why, despite their efforts to assuage people, so many people will not trust this government.

The backdoor legislation means that at a later date, after the code is released, they could request a backdoor to the app and _no one_ could talk about it. All the legal provisions are there.