What did Robert Edward Lee think of slavery?

Answer 1

He tended to agree with the prevailing Southern belief that slavery was a natural arrangement of black and white.

His attitude to slaves was tested when he became executor of his father-in-law's will, involving the management of a large estate. The old man had ordained that the slaves would be freed as soon as his estate was settled. Some of the slaves thought they understood that they would be free immediately after his death, and became rebellious.

Lee found it necessary to apply harsh punishments to the mutineers, including fifty lashes to the worst offenders.

Late in the war (too late to make any difference) Lee was one the generals who suggested recruiting slaves into the Confederate army.

As general-in-chief of the Confederates, he can perhaps too easily be painted as the slave-owners' champion and his later admirers liked to present him as being anti-slavery. That is not a realistic claim.