Why can’t I control Hulu with PS4SecondScreen?

Okay so I recently sold my ps4 controller (Needed some quick cash) and downloaded the PS4SecondScreen app, I can’t control the home screen well but when I try to go to Hulu I can’t control it, like it won’t swipe left, right, up, down. Is there a reason I can’t do this? What would be the sense of creating an app to control your ps4 but you can’t control it in-app.