I would hope MPH makes a small profit....servers need to get paid, owners need to eat.
The pool fee

The owners are probably millionaires for a long time now.
I seriously doubt that.
The Ethereum Pool at MPH is mining at 1212 Gigahash. This is about 2.8 million $ worth of mined ethereum each month right now. MPH gets 28.000$ in fees monthly from the ETH pool only. I am lazy to calculate all the other pools. But I'd say MPH gets about 100k $ each month in pool fees only. If you add the withdrawal fee it's maybe 105k$ or 110k$.
I doubt that the hardware,hosting,employees cost that much....
If you know better I am all ears.