I guess that's one way to look at it, but your analogy is flawed. I'm mostly unaffected by anyone else having their account hacked, whether or not they've implemented two-factor authentication.

But I really believe they just want my phone number. Why do they tell me the security is "low"? Why not "medium"? What if I don't have a cell phone? Without giving them a number, I guess I live on a low security site? It's FUD, just like those popups telling me my security settings on my PC are "low", or that I have a "virus".