Massa Tom Lea's a difficult character to pin down. It's not that he exists in a moral gray area a la Walter White—he's definitely a bad dude. But in Roots we get a glimpse at the human-ness at the heart of this total amoral scumbag.
Massa Tom's obviously a monster: a rapist and slave-owner who abuses people on a daily basis. But when we view him through Chicken George's eyes—the eyes of a man desperately trying to figure out his relationship with his biological father—we gain a slightly more nuanced understanding of this despicable character.
At first glance, Tom Lea should be the embodiment of the American Dream. Born from a poor background, Lea used his success as a cockfighter to rise up the social ladder, buy himself a farm, and amass a small fortune. But instead of embracing this success story, Massa Lea runs away from it, ashamed of his class background.
Take a look:
Massa Lea's brothers were dirt-poor crackers of the sort that not only the rich planters but also their slaves sneered at. Time and time again he had seen how embarrassed the massa was to meet any of them. (93.30)
This shame is most embodied in his insane decision to continually bet against a rich English cockfighter despite not having enough money to cover a loss. He even doubles up after winning the first time—and then loses. That's legit nuts. More than that, however, it reveals the extent of Massa Lea's deep insecurity.
But nothing can explain the horrendous abuse he inflicts upon Kizzy and the other people he enslaves. He frequently makes degrading comments about black women in particular, even in the presence of George, dehumanizing them and framing them in animalistic terms. To Lea, black women are objects to be taken advantage of…and as we sadly see, that's something he does frequently.
Lea's similarly dehumanizing towards George, his biological son. While it's clear that Massa Lea holds some amount of affection for him, and maybe even wishes at times that he could embrace him as a son, his racial beliefs prevent him from even considering it. And that's putting aside the awful circumstances of his conception. In fact, it's not until he's lost everything that Massa Lea even alludes to a real relationship between the two men.
Take a look:
In Massa Lea's hollowed face, his eyes were rheumy, then with high, cackling laughter he rushed with widening arms to hug Chicken George, who sidestepped. Catching Massa Lea's bony hands, he shook them vigorously. (108.23)
As we can see here, however, Chicken George rejects him. This represents George finally letting go of his expectations of Massa Lea and realizing that the man has been nothing but his oppressor the whole. Ultimately, Lea deserves far worse punishment for his horrendous actions than this lonely end, but it's the closest thing to poetic justice we're going to get.