Dumbledore's full name is Albus Percival Wulfric Brian Dumbledore. Albus means white, or stands for wisdom. Percival is the knight in the Arthurian legends who finds the Holy Grail, and is pure. Wulfric was a Saint, known for prophecy and miracles. Brian is Celtic, and means strong. Dumbledore is Olde English for butterfly.

So by his names, JKR is telling us that Dumbledore is a white, pure, wise, strong, miracle working, prophecying butterfly.

Huh?

Anyway, all of the names have positive meanings, as opposed to names like "Draco," which can mean dragon, or snake that turns into a dragon.

I agree with ProfCrash for observing that Dumbledore has ulterior motives for his actions, and there are probably multiple layers to his reasoning. He said as much himself, in his explanation to Harry. In Harry's case, however, Dumbledore's actions became clouded by his affection/love for Harry. He wanted to spare Harry as much as he could, because he cared so much about him. Recognizing that error, Dumbledore must now be resigned to "spend" Harry as he would any other of his pieces in his chess match against Voldemort. No one will be above being sacrificed.