They care because Google made a policy that your site gets less hits the less mobile friendly they are. That's my theory anyway
What Google did lately was saying that the site should be the same for both, unlike Chase's m.chase.com, but should be adaptable nicely to use on mobile. This is done with a Responsive Design website.
But Chase isn't doing that so far. So what different compliance with Google's desires do you see for not allowing a person to use the desktop site if he so wants to?
(in Chrome on Android Chase loads just fine if Request Desktop Site is checked.)