It was most likely the writers slightly altering the rules of Hell over time

In 2x13 Uriel was a manifestation created by Luci

I have a quality soul to sell at a reasonable price of £900,000,000,000,000,000,000,000,000.00 pound sterling

"So why in Malcolm hell he said he was alone where was the demon"

Its because Malcolm said he loved life

All aspects of it, including people.

So they robbed him of food, water, entertainment, and even people. That was his torture.