I believe that when you are "Show all sections on one page" view, going to "EN-template-C-191204" is exactly what one would see if the "Week 1" breadcrumb could be clicked. Since there is no difference, and maybe trying to confuse people that there is a difference, the "Week 1" breadcrumb is disabled.
The target of a section link is the section id on the course homepage, not the course homepage itself. That distinction is useful to reduce the need for scrolling on the course homepage.
Yes, you have a good point. I think what you are implying is that if Week1 could be clicked, that one would be taken to the course page, but the browser would position this web page to Week1 (in your example.)
Have you checked the Tracker system to see if there is a feature request for this? If not, create one.