I know there are a lot of theories that describes Dumbledore as evil and some of them are also convincing.
But hear me out. Dumbledore's action might be manipulative and questionable but he was never evil. His sister's magic was out of control because of being bullied by muggle children. His father was sentenced to Azkaban for killing the perpetrators(as many father would do.). Her sister's uncontrolled magic probably resulted in the death of his mother. And lastly his duel with Grindlwald resulted in the death of his sister. His life was full of tragedies. It was fortunate that he didn't want to rule the magical world otherwise there would be no need for Voldemort.
Now, as for raising Harry as a lamb for slaughter, it is a 'BS' theory. Remember when Harry died in the battle of Hogwarts, he met Dumbledore.
I think Dumbledore planned all this just so that Harry could live after Voldemort was killed.