The reason why some people use the spam signal to unsubscribe is because most of these email lists were not _explicitly_ requested by the people. Not only that

The reason why some people use the spam signal to unsubscribe is because most of these email lists were not _explicitly_ requested by the people. Not only that but unsubscribe confirms the existence of an email address. I'm hoping that the machine learning approach to spam completely collapses so that we're forced to do something more effective.