It is a demonstration of the strong social pressure to conform to one's environment, even if that means going against their actual preferences.

>Also, there's no indication that person's friends actually pressured / shamed the person into working for Obama.

If only overt and direct kinds of social pressures mattered, then we wouldn't be having similar discussions about structural and subtle forms of racial bias, gender bias, etc.

It's not the intent of the giver of (unintended) pressure that matters, it's how the receiver interprets and responds to it.

Yes, but that is not an exclusive political/politcal-correctness phenomenon, so it's not particularly interesting. This is a universal phenomenon in all walks of life. This is a phenomenon experienced by liberals in deeply conservative areas. This is a phenomenon experienced by atheists in deeply religious areas.