Not sure if the questions are rhetorical, but in case if not, the history of allowing that is reflected in www-talk archives [0], and in articles such as [1]. Basically (and AIUI), some publishers wanted that, users didn't object too much, and it happened -- same as with a bunch of related technologies.

[0] https://lists.w3.org/Archives/Public/www-talk/

[1] https://www.w3.org/People/Raggett/book4/ch02.html