Disclaimer: I am against ChatControl.

> Does anyone believe that predators commit those heinous offenses because of the availability of encrypted channels to distribute those products of their crimes?

Who says that? I don't think they say that.

> The authorities really think every predator will just give up and stop abusing just because of that?

Nope, they think they will be able to arrest more predators.

> More likely of course, those criminals will just use [...]

You'd be surprised how many criminals are technically illiterate and just use whatever is the default.