Because omitting it is the same as sending it to “all”, which usually doesn’t make sense when the stylesheets are almost always designed JUST for screen media. As a good rule of thumb if you see a <link rel=”stylesheet”> set to media=”all”, or lacking media=”” altogether, you are looking at code written by assclowns not qualified to write a single damned line of HTML or CSS.

And yes, I realize that means 99.999% of all code made by the turds who CREATE HTML/CSS “frameworks” like Bootcrap or Failwind… and probably in excess of 80%+ of the entire web. Apologies for pulling percentages out my backside.

If you aren’t saying what your style is actually FOR, or think that sending screen media style to everything is acceptable, one has failed to even grasp one of the basic reasons CSS even exists.

It’s why I think that media=”all” should be stricken from HTML, and browsers should start rejecting pages that don’t set media=””, even if it would break the vast majority of websites.

I do not let that level of ignorant “eye cans haz teh intarwebs” coding fly in my systems.