this in particular comes from the addressee
I think the ruling's main point/distinction here is that while submitting a form might be getting consent from the addressee (the person submitting form might be the addressee, if they own the e-mail address they entered), but we can't know that for sure until they confirm by clicking a link in the e-mail.
Only then do we know for sure that the actor submitting the form was the addressee and that the consent ostensibly received via the form was in fact from the addressee. But it could otherwise be the case that they entered someone else's address, and you can't give consent on behalf of someone else!