I thought Ruby was obsessed with the IDEA that whiteness was a ticket to happiness, but as time went on, she realized that the real ticket to happiness was to be comfortable in her own skin (literally AND figuratively). I saw it as a statement on the futility of trying to "pass" for white.
I saw Ruby as both victim and aggressor - but as aggressor, she was well-rounded enough that I saw her motives in a sympathetic light.
On the one hand, and similarly to her trying to pass for white, women don't "win" by BECOMING the worst they see in men. But on the other hand, I was glad she stood up for the woman she, herself, had been mean to earlier. (Women often side with men against other women, when they ought to stick together, don't they? Sometimes, they figure it out. Sometimes, it's too late. I think for Ruby, a lot of the lessons learned just came too late.)
I saw Montrose as a generational abuser, but mostly as a mean drunk covering up his own pain in a combination of denial and self-flagellation. He couldn't openly love who he loved; he had to live a lie. For men of his generation, being gay wasn't just frowned on - it could get you JAILED. Tic wasn't his and he knew it from day one, but Tic was also the social proof that he needed in order to pass for straight. Tic bought it like everyone else, and thought Montrose's anger was because Tic couldn't live up to Montrose's expectations. In fact, the opposite was true: Montrose couldn't live up to his own, his dad's, his wife's, or his son's.
In the end, we learn his backstory and see that he was misunderstood and angry because he kept his secrets, when everyone around him - it was obvious to the VIEWERS, I thought - got to live openly and would have accepted and loved him just for being himself, for once. In fact, the other adults who helped him to keep his secrets at least got to enjoy love and lovemaking. In that respect, his story and Ruby's were similar ones that showed the damage to a person from internalized hate.