I hope you realize the irony of "protecting your identity" when you link your Github on HN (that has your real name) and which, in turn, links to your resume, portfolio, personal website, and (presumably) private email address.
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.
Stop being a dick.