Today I learned: If you use #Chrome and are annoyed by those "Sign in with Google" dialogs stealing keyboard focus on certain websites, you can disable it at the browser level.
In the address bar, type or paste in "chrome://settings/content/federatedIdentityApi" (without the quotes. You should land on the "Third-party sign-in" Settings page.
On that page, there'll be two radio buttons: "Sites can show sign-in prompts from identity services", and "Block sign-in prompts from identity services". Set it to the second one, and you should find that the problematic dialogs are no longer present.
I use the uBlock Origin browser extension and I was able to block it using that.
This is on Mac OS (MacBook). I'm not sure if this will work on any mobile devices.
@ahimsa_pdx I use UBlock as well, on Firefox for Windows. Have you blocked it manually? How one does that?
@clv0 Yeah, it was not automatic, I had to set up some filter (or rule or whatever it's called) for this.
I can't remember exactly what I clicked on to set it up (lots of brain fog and memory problems!) but it works. I've seen others post about this solution, too.