It may be easier to believe they are being disingenuous but the real answer is probably that they are in fact racist.
Its a hard truth to swallow.
The rest of this isn't directed just at you astura.
If this was some random Facebook or 4chan comment would you be so quick to come to that rationalization?
I feel we like to think the individuals we associate with on HN are like minded. To admit they aren't is almost a personal affront. To keep the disillusion going we must rationalize and make up excuses for them or how they behave.
But sometimes a duck is a duck.