I think you're clinging too much to the interest a person gives when it downloads your work. If they don't decide to keep tabs on you after downloading, then I think it's better to let go. From what I gather, you want to employ an "aggressive" marketing strategy I disagree with and find kind of disrespectful.
I don't mind Itch having my email, because I trust them to handle it carefully. Allowing the feature you're asking for would at least damage that trust. I've played a lot of games here. I don't want every dev to have a direct line to my private email.