I think all of the people who've read Kindred can agree that Rufus committed terrible actions. He raped a woman he claimed he loved, indirectly played a role in her husband's death and turning her into his slave, and forced her to live through an abhorrent pretense of affection and childbearing under the constant fear of violence. This women, who you might know better as Alice, eventually killed herself due to Rufus deciding SELLING HER CHILDREN (even if it was a only as a reversible punishment) was a good move. Of course, don't forget Rufus' role in Dana's own traumatic experiences, including separating Dana from her husband (through refusing to send Kevin her letters and then lying about it), shoots at her, sends her to work in the fields where she is severely whipped as a ridiculous punishment for her not saving his father, and directly causes Dana to lose an ENTIRE ARM. Gee, Rufus, good job!
Yet, as a child, Rufus seems innocent and kind, helping Dana escape the plantation and acts friendly towards Nigel. What happened to that version of Rufus? It leads us to a bigger question that Kindred explores within the novel: Nature V.S Nurture. With even Dana, who directly experiences violence through Rufus' actions, struggling to distance herself from him and see him as a "bad" person, it leads to a couple of questions: Is Rufus a "bad" person, or is he simply a product of his environment? And perhaps a better question: if Rufus's horrible actions can be proven by environmental factors, does that excuse or remove the blame from Rufus?
Of course, many external factors during Rufus' life play a role in how Rufus perceives the world and one could argue there is a direct influence on the environment on Rufus's actions and behavior. For example, Rufus, with his father portraying relationships as ones that can be violent with enforced punishment, his mother painting an overbearing, almost obsessive idea of love, and living during a time period with a normalization of the commodification and ownership of human beings, obviously did seem to play a role in Rufus's incredibly twisted impression about love and thus his relationship with Alice and Dana.
However, even with these outside factors perhaps providing an explanation for Rufus's shockingly awful character, it does not justify Rufus as a "good" person or mitigate the harm he's played a role in. Sure, the factors may have influenced his actions, but he, like anybody, has the capability and willpower to chose the right decision. Rufus had so many chances within the book to turn Alice and Dana's situation around in a positive way, yet every time he chose the option leading to his own best benefit. If Octavia E. Butler wanted to portray Rufus really as a "good" person, she would have shown him rising ABOVE his environment and still choosing to be benevolent throughout the pressure. Alas, Rufus allows himself to succumb to his selfish and base desires, turning himself into quite a despicable person by the end of Kindred.