Yet another annoyance that follows us around the web: “Sign in with Google”
You can disable these prompts, but Google buried the option:
Manage your Google Account ⇢ Security ⇢ You connections to third-party apps & services (“See all connections”) ⇢ Settings (gear icon) ⇢ Google Account sign-in prompts: OFF
direct link to disable Google Account sign-in prompts: https://myaccount.google.com/connections/settings
“Sign in with Google” prompts even appear if you are not signed in — and when you don’t even have a Google Account. (screenshot example: Medium in a new private browser window displays a rather larger prompt)