"Why not? It seems like some people are eager to not be on any mailing lists, and the worst downside seems to be that they won't able to reset their password."

"Why not? It seems like some people are eager to not be on any mailing lists, and the worst downside seems to be that they won't able to reset their password." I think you missed his double-negative there - he is saying that you shouldn't not be letting users sign up with ... ... which I agree with ...