The implication is clear in your sentence; you really believe that since Lincoln was part of the Illinois legislation he was responsible for , "very cruel laws as relating to blacks," and that he helped pass, "laws aimed at preventing them from settling in Illinois, and for treating them horribly when they did."???
I gave you a link to a message in which this very assertion is being made, and another link to a book which shows such a law was actually passed during Lincoln's tenure in the Illinois legislature.
I did do a bit of digging and found that Lincoln was one of five who voted against one discriminatory law, but the message I linked for you asserts he did vote for other laws of a similar nature.
But don't seize on just the Lincoln bit, also address the Illinois white citizens rounding up Free blacks and selling them into slavery in the South. Acknowledge that Illinois, as a state, was just as racists and hateful as people try to make the Southern states out to be.