Because the Discord app takes up too much bloody space. These are instructions I found online and they do work.
Discord has some hard-coded placements in the app, so they also put in a limit for the minimum size of the window. Well, fortunately, they also told us how to remove that in a Reddit post. You'll need to edit the settings.json file to do so. You can find this file at:
Open the file and add
between the IS_MINIMIZED and WINDOW_BOUNDS lines.
Once you've made the changes, save the file and restart Discord (close it through the systray icon). Now you should be able to resize to however you'd like.
The only issue I've come across is the "X" is off-screen in the Settings, so I have to widen the window to click it.
Also, if you use the BetterDiscord plugin (and you should!) this is a good css theme for collapsing the sidebar.
Having successfully invaded both America and Canada from her home base in Windsor, Paisley has become horribly corrupted by the world. She hates active voice and wishes to god Twitter had an edit button. Dedicated to "creating the greatest 'Ship of them all", she ponders horribly terrible, idiotic things for your amusement.