I use a system at work that is 100% web based. I have 2 4k monitors in my desk. Why are the apps formatted for viewing on a phone? I've gotten to the point of hacking the CSS on every page just to make things usable.
At the last version upgrade, the developers made some changes to the interface. They couldn't be bothered to change the existing CSS, so they just put !important on all the new stuff.
It's kind of screwed to say. But a lot of people entering the work force grew up with phones and tablets as their main computer. It's the mind set they have that everything uses touch interfaces.
I'm not saying everyone or even most, but for a good portion it's their default computer experience.