Low fees signals to the network that a channel needs inbound liquidity. One person's gain is another's loss, but that has to happen in a closed system. It's an inherent property of bitcoin, and it is not a predator-prey relationship. When you stand to have something to lose (in this case, a well positioned channel with good outbound liquidity) then if this has value to you or others, you will be able to extract that value from it (hence fees). If there's nothing of inherent value to begin with (in a fiat system) then such a loss becomes more tenable.