That is a sad case of people proving that once the tables got turned the once who once was oppressed will happily deny others the right of free speech.
And, the majority, the ones who care less about right and wrong as long as they are on the correct side, will happily follow along, just as they did when Catholics ruled, just as they did when White Straight ruled.
FWIW I'd apply a "does it affect how they behave at work?" test.
If I had a very good developer who was perfectly courteous and professional at work but in his spare time was (say) a member of the Westborough Baptist Church or the Socialist Workers Party I'd not be concerned.
I wouldn't as well, but as soon as that developer would become representative of my company and people would start to bring it out in connection to the company, I'd start to worry about my image.
For your typical standard worker it doesn't really matter what he/she does outside of work, as long as it doesn't damage the company - which is pretty hard unless you really try, since nobody outside gives a damn about some noname employee. For someone very high in hierarchy it actually becomes much easier to damage it, so you have to draw a line somewhere. If your company, supposed to promote messages of equality and taking pride of its supposed openness, elects someone who actively supported means of oppression against minorities as its representative and people start to react, there might be something worth reconsidering in this situation.
It's interesting which way the double standard swings on this; for instance, the McCarthy-era Hollywood blacklist was exactly the same kind of "social consequence".
And, the majority, the ones who care less about right and wrong as long as they are on the correct side, will happily follow along, just as they did when Catholics ruled, just as they did when White Straight ruled.