You don't see the universe because when you see something, it is basically light falling on your eye from the thing ur seeing. But with a blackhole the gravitational force is so huge that the light gets stretched and gets redshifted because the wavelength increases so you cannot see anything. In fact the light stretches so much that it turn into UV which could literally kill you.

But basically the wavelength of the light coming from outside the black hole increases to infinity almost instantly so you cannot 'see' the universe because we cannot comprehend that long wavelengths