It's a governance.

The executives don't want anyone else to be able to use the messages in a malicious way, so they decide to cut it at the sources of the messages i.e. e2e encryption.

This is like: corporate emails being deleted after 6 months. When an authority asks for emails from the last year, they can say they don't have it.

Now the authority can ask for the emails not to be deleted at all but then that will be a different battle the authority has to fight.

Corporate emails often don't involve pedos/terrorism, so there's much less push to retain corporate emails forever.