If I got banned from Google, then almost 20 years of emails, 1TB of files on Google Drive, are gone. Many of the services I use that use email as a second factor, I'd be locked out of. (And before you ask, yes, I use an authenticator whenever I can, but for some reason some services decide to still only let me use email as a second factor). If I forgot my password at any site, can't reset it. Not to mention that I can't use my Android phone out of the box without installing custom de-Googled firmware.
I suppose the same argument could be made that I don't have a fundamental right to use Gmails mail servers, but as I pointed out above, it is more than just an inconvenience, it could actively be harmful to my digital life, because Google has its hands on almost all things digital.