> But for a pseudo-legal argument: Google participates in a form of product tying[1] by requiring you to create a Google account in order to access Google Groups (which are publicly-run mailing lists and an unrelated product to their account service).

That seems to be false; I can read mailing lists hosted at Google Groups without logging in (for instance https://groups.google.com/a/groups.riscv.org/forum/#!forum/i... opens for me without asking for a login). I'm subscribed to that mailing list from an email address which is not a Google account, and I didn't have to log in to any Google account when I subscribed. I can post to that mailing list directly from a normal email client, through a non-Google email provider.