Personally, I would engaging with the caste system for any purpose other than to destroy it is very wrong. I've seen plenty of upper-caste people assume someone's caste based on their appearance. They may have been wrong, but I fail to see how that is relevant, as I'm not justifying or explaining, just describing. If your particular objection is to the word 'determine', then I think we're getting hopelessly bogged down in semantics.