It's very difficult in practice to shift the blame to the website. Even though the browser would be right in refusing connection, the net effect is that the user would just use another browser to access that website. The proper workaround (Firefox shipping intermediate certificates), doesn't actually damage security. It just means more work for the maintainers. That's a fair tradeoff for achieving more market share.
It's the same reason why browsers must be able to robustly digest HTML5 tagsoup instead of just blanking out, which is how a conforming XML processor would have to react.
It's the same reason why browsers must be able to robustly digest HTML5 tagsoup instead of just blanking out, which is how a conforming XML processor would have to react.