Why are tools like github and gitlab like this? All the work has to be done server side, the JavaScript stuff (especially hiding the tree when the window is sma

Why are tools like github and gitlab like this? All the work has to be done server side, the JavaScript stuff (especially hiding the tree when the window is smaller, that's the whole point of the thing!) is just annoying. Github's PR UI is nice but it's times like these where I wonder if it really improves on a mailing list and a few cgit instances.