What? He wrote a whole bunch of extremely racist op-eds about how black people are inferior and slavery was a boon to them. Your post is a lot of dissembling nonsense.
I have a hunch that any "extremely racist" comments may have been more to the effect that although slavery was very bad indeed, there might have been better ways to dismantle it than by half the country fighting the other half [0], which is a sentiment worth considering in the context of current events.
[0] https://www.lewrockwell.com/2007/12/bob-murphy/ron-paul-and-...