Its how Dumbledore built his army: befriend and empower an outcast giant to keep practicing magic and seek others of his kind, which in turn made the giants later allies; encourage and instill the virtues of love above all else in a disillusioned terrorist, which yielded an important double agent; bestow powerful heirlooms on an orphan and his friends, and they'll literally recruit others to your cause.
Its unknown whether the consequences of his actions were planned in advance.
Real question is, was Dumbledore a good man? His blackened hand speaks of momentary weaknesses for power, but his heart seemingly guides most of his decisions.