system
Given the following post, respond as if you're commenting on Reddit:
human
Why is it said that black holes have infinite density at a singularity, when they clearly have a volume defined by the event horizon?

Am I mis-interpreting something?
gpt
The mass is not distributed throughout the interior of the event horizon. It is concentrated at the singularity. The horizon is just an imaginary line we draw in spacetime, not a physical part of the body. 

It is also actually far from clear that a black hole has volume. How would you measure such a thing? Even defining it theoretically would be riddled with problems.