Just curious, for your personal experience do you know the caste distribution of your indian friends? I too haven't seen much of anything casteist at work or among my friends, but I'm not discounting that it exists and potentially at larger scale than I've personally experienced especially since almost all my friends are brahmins or the caste right below that. You'd have to have a large enough sample of low-caste friends to really understand the experience of low-caste individuals.