If cloud mining would be guaranteed to be profitable, why should they offer the service to other users and not mine completely themselves?
They only offer this service to others so they can use other people's money to build up THEIR own hardware infrastructure without investing their own money, and then even profit from any mining you do. For them, it's a 100% win situation with no risk, and they keep the hardware ;-). All of the risk lies with you, the user.