It would be in a miner's best interest to deny profitability because any additional computing power added to the network decreases the bitcoin income of the existing miner.
If miners were perfectly rational and willing to lie, then yes, it would be in their best interest to deny profitability.
However, most people posting here like to think that they are honest people. As such, they express their "true" opinion, and not lies. And most people who mine do so because they think it is profitable - just like most people who flipped houses in 2006 did so because they thought it was going to continue to be profitable - even when data was staring them straight in the face that houses were getting too expensive. People will go to extraordinary lengths to continue to believe easy money will keep coming.