The only motive of miners is profit. This is by design. How else could you incentivize a bunch of random people to find partial SHA-256 collisions? Security is

The only motive of miners is profit. This is by design. How else could you incentivize a bunch of random people to find partial SHA-256 collisions? Security is ensured by the economic incentives baked into the protocol. Security is the by-product of economically selfish behavior.