As I mentioned before, interracial couples were not illegal in Boston in the 1950s, but illegal in Texas in the 1950s. It is debatable whether that is a lisbian couple in the trailer since they could be sisters. As far as that open lisbian couple goes, it is in a post-apocalyptic wasteland so things like survival and defending against raiders, feral ghouls, and super mutant attacks are more important than someone's sixual preference or religion. Here is a Wastelanders reaction to someone coming out.
A: I don't know how to say this, but I am gay.
B: Who cares.
A: It took me forever to work up the courage to come out of the closet and now you are telling me that my fear was completely misguided?
B: Fraid so. Now pick up that Laser Rifle. Raiders are about to attack.
As far as racism goes, there is a ton of that in Fallout. Except that instead of being racist against African Americans or Asians, it is against Ghouls and Synths.
The 1950s argument is important since Fallout is based around our view of what the 1950s would consider the future to be. People bias their view of the future on the values they have. Since the 1950s is intolerable to gays, then 2077 would be intolerable to gays as well. However, 2078 won't be since the complete destruction of civilization is a great way of removing all cultural norms.