That's what I said. Your can withdraw consent (which you never gave), or tell them that you like color purple more than you like red, but it will have no effect

That's what I said. Your can withdraw consent (which you never gave), or tell them that you like color purple more than you like red, but it will have no effect since it's not the basis for processing it. The privacy policy should list what data they collect and for what reason. However if they process your e-mail for several purposes based on different legal basis (for instance they also use e-mail for marketing purposes), they should stop using it for these reasons which you requested (for instance - all applicable) where consent was the basis for processing.