is defending his daughter Rae Dawn
-- telling TMZ she was just being honest when she said Oprah would have been a "field" N-word back in the slave days ... because that's just the way things were.
"If you think of what [Rae] said, she said back in the day Oprah would be working in the field because shes not that beautiful ... whereas if you're beautiful, you're part of the master's bedroom."
Tommy continues, "Knowing Oprah, she would probably read [Rae's comments] and just chuckle and probably agree with Rae Dawn ... she probably would be working in the field."
There's more ... Tommy says he doesn't think Oprah would have STAYED in the field during slave times, because she would have used her "charm and intelligence" to become a "house lady."
And even though Rae called Oprah fat and ugly and a "brown-noser" ... Tommy still thinks there's a chance Rae and O could work together again in the future.
Dude, how HIGH are you??