Why does Yahoo keep breaking things?

The site is for knowledge seeking questions, not rants. You gave ZERO information regarding whether you are a mobile or desktop user, or how you're accessing the site (e.g., what browser or method).

For desktop users, category access is the same as always. Any pinned categories are still at the top left of our screen, and below that is the full category list. Nothing is "broken". Yahoo has made changes to the mobile version of YA but just because something is different doesn't mean it's broken (although sometimes it is). It's likely you'll just have to learn how to navigate using the new format, if you want to continue to use the site OR switch to a desktop device.

Not sure where the category list is for mobile users, but swipe right and see if that helps you access them. I've seen other users post that there are additional features/menu options when you swipe.

1 word Competition there trying to Compete with Other Sites Even tho they dont have to

Maybe the problem is that you aren't bright enough to figure out what you are doing wrong

what are you talking about? My "thumbtacks" are working just fine