Monmouth, Bismarck, and the limits of surrender comparisons

Was finishing the crippled Monmouth equivalent to the Royal Navy's destruction of Bismarck?

Not entirely. Bismarck might still be recovered and British forces feared submarines, while Monmouth had no realistic prospect of escape or repair.

Bismarck still posed a recovery risk, and British commanders could not allow the battleship to be towed home. Their ships were short of time and feared submarine intervention, making a rapid finish operationally important. Monmouth was already incapable of returning home, while von Spee faced no comparable external threat after the other British ships had been driven off. The two sinkings could therefore both be lawful without being strategically or morally identical.