What is the difference between a thief (sāriq) and a plunderer/usurper (muntaḥib), and why is the punishment of cutting applied to the thief and not to the plunderer/usurper?

Cutting off the hand of a thief for three dirhams, while not cutting off the hand of the embezzler (mukhtalis), the usurper (muntahib), or the one who seizes property by force (ghasib), is part of the perfect wisdom of the Lawgiver. This is because a thief cannot be guarded against, as he violates the secure enclosure. This is unlike the usurper who takes property openly, and people can repel his aggression, and the embezzler who takes property at a moment of the owner's heedlessness, and against whom one can guard, and the one who seizes property by force, whose situation is even more apparent. The aggression of these individuals can be repelled by beating, imprisonment, and punishment by seizing their wealth.