Allah gives people what they want if they insist on it. It's us who aren't always wise. Hell is nothing other than the physical manifestation of separation from Allah. This is a choice some people make in this life. They want separation. They don't believe us when we say there's a life after this life and you're going to get what you ask for. They mock the very idea. We take it on the chin.
When you take on a belief, you intend to keep it forever. This is why beliefs are compensated eternally. Attachment to Allah is physically manifested in Paradise. Separation from Him is physically manifested through Hell.