I'm a non-dalit Indian working in silicon valley. I know that caste based discrimination is still prevalent in India and not surprised that it continues in here in silicon valley as well amongst Indian community but I'm surprised to read this part in the article. I have never heard of someone doing a scan for sacred thread. Also, it's worth noting that most non-dalit people also do not wear this sacred thread so whoever is doing this scan isn't familiar with India or probably this part is made up in the article.
That said, I know that it's much harder for a dalit person to progress in India as the society still tries to pull them behind. Indian govt has reservations in colleges and jobs for dalit community, which I believe has helped the community a lot in last 50 years or so, helping many to bring their families out of poverty. But, still there's a long way to go. Also, a long way to go for non-dalit community to abolish this discrimination.
My heart goes with our dalit brothers & sisters and glad to hear that their issues are being discussed in silicon valley as well now.