I've never understood why Gmail and Hotmail/Live/Outlook don't take a user's own indications as gospel. If I whitelist an email address I want those messages, I

I've never understood why Gmail and Hotmail/Live/Outlook don't take a user's own indications as gospel. If I whitelist an email address I want those messages, I don't care if [you think, perhaps erroneously] they are spam. Possibly the worst is not allowing replys. I mean if a customer sends me a message, and you block the reply as spam how is that serving that customer? Sure mark it, remove viruses, obfuscate links, but let me reply to someone!