My email address isn't private, and I am OK with these comments being linked to my real identity. But—and this is important—I elected to do that.

It's far more of a dick to force your users to reveal their identity.

EDIT: to be clear, OP is not a dick, but there should be a non-session or non-sso signin option (as there is now) if I want to preserve anonymity for what is essentially a (polished) toy.