Lincoln's views on slavery in, say, 1850 were similar to those of most Northerners -- they understood that slavery in the South was a precondition for Union, but did not want it expanded to Northern states or Western territories.
Like Jefferson and many others before him, Lincoln thought freed slaves should be returned to Africa.
By 1865, Lincoln's views on both slavery specifically, and African-Americans in general, had changed hugely, especially following meetings with black leaders who told Lincoln they did not want to return to Africa, but rather wished to live in the United States as free men.
So I would not blame Lincoln in 1865 for views he and many others had held years earlier.
Unfortunately for them, their position is unsupportable by the US Constitution. Slavery was recognized as a property right under that paradigm. You can't ban people from owning their "property", even if you disagree. The Constitution explicitly forbids the laws of another state from freeing people "held to Service or Labour in one State, under the Laws thereof."
If the constitution says that no laws of any state can deprive a man of his "person(s) held to Service or Labour in one State, under the Laws thereof," how can you possibly restrict slavery in another state?
So long as a man leaves a state where slavery is recognized, and goes to a new state, how is he not protected by the US Constitution from bringing his slaves with him?
What is your legal argument here?