Because developing on that many web standards when the other three have such a huge market share is unnecessarily onerous.
Not supporting one browser or another is rarely if ever a stand against that browser, it's just a decision based on living in reality. I've used and liked Opera in the past, but I've never once tested so much as a web page in Opera since I stopped using it as my primary browser.
There's always a post like this. Who gives a shit about Opera at this point? It's hard enough making a complex web app work on IE, Chrome and Firefox as it is.
When they take away opera they will take away firefox, then they will take away the next one. One day we will all be using chrome.
I think they should warn about compatibility but allow us to proceed anyways. Often when I spoof opera to identify as firefox everything works fine. The `built only for this browser` scheme treats the browser as the platform and not the internet as the platform. I understand the practical motivation for perspective, having spent many hours making sure my design worked in IE and Firefox, but I dream of a world where every-browser will render things identically.
Ultimately, its called a webpage not a chromepage.
I like private keys instead of passwords in theory, but in practice, I'm scared that I'll misplace the private key file, rendering all of my data lost forever. Private keys can also be lost (stolen laptop?) or misplaced. Or what if you're traveling and your laptop gets busted, how do you safely and quickly transfer a private key from your home storage to where you are? I'm not a crypto-expert, maybe these questions all have easy answers--but they're not obvious, at least.
Memorable passwords are in your brain for the long-term, and can't be lost or stolen. (Well, aside from improbables like torture.)
[1]: https://help.github.com/articles/using-ssh-over-the-https-po...