The general "Safari is the new IE" meme comes down to Apple having different priorities than other browser vendors (notably Google) when adding features. Right now the complaints tend to center on Service Workers and WebGL, but there are quite a few browser technologies in which Safari support lags.
The things Apple priorities -- battery life and security, for instance -- don't mean much to most developers who would prefer to be able to use <insert sparkling new web tech here> without worrying about shims, and so on. Problem is, you can't quote that "there are 1.5 billion Android users out there" with this in mind and keep a straight face. A huge proportion of those users are NOT using a browser this group wants to target.
The things Apple priorities -- battery life and security, for instance -- don't mean much to most developers who would prefer to be able to use <insert sparkling new web tech here> without worrying about shims, and so on. Problem is, you can't quote that "there are 1.5 billion Android users out there" with this in mind and keep a straight face. A huge proportion of those users are NOT using a browser this group wants to target.