I’m not sure if that’s meant as a disagreement or agreement?

There is no scenario where it’s okay to add information to my emails without my opt-in permission.

Highjacking your email without your consent in an effort to spread itself to your contacts, is what a virus does. Coupled with all the annoying pop-ups and sounds that you already recommended disabling, there’s only one conclusion here.

Does it do this by default? Because if so, the proper reaction should be “uninstall”, not “turn it off”. That’s a pretty big violation of trust, IMO.