The web is not about me. But the websites I create are not for everyone. They are for my users.
My users are professionals, on desktop, with a mouse and keyboard.
Knowing who are my users allows me to do better design. I make the best experience for THEM. Not for you, nor for all your friends using different hardware.
It doesn't mean I don't care about loading time or how things are displayed on the screen. It means I do so knowing in which environments it will happen. And yes, it might means you will be excluded.