Why do people use Dalit/lower caste as insult?

[Вavhat]

I saw in this forum and other anthropology forums, when people are classifying indians sometime some indians say someone is or looks similar to Dalits as a kind of insult. But in real life i saw there is no big difference between the looks of Dalits and brahmins . There's no way to tell which caste someone is by just looks. And dalits all don't look the same. now even some non-Indians think dalits a certain way and started using dalit as insult. In India the caste system is being destroyed any way, I did not know that people outside India know about castes like Brahmins and Dalits and even call them "lower" or "upper" castes ... why is there a misconception that dalits look or act in certain way when there's almost no difference (physically) between the different castes?

[Sekarotuinen]

India needs a better religion, one without a caste system. Islam is the second biggest religion, so that is the natural choice, but many others work too.

[silver_surfer]

Caste's look differently? You really can't tell- fairer skinned people from north India might just tend to be from the traditionally 'higher' castes. It's an interesting topic though, there's a theory that the caste system was established when the proto-indo europeans, the 'Aryans', invaded India and the possibly-dravidian denizens of the erstwhile Indus Valley civilization were enslaved and made 'Shudras'. Not too much proof for the theory though.
Also, skin color is VERY heterogenous, varies within all castes, much more so all regions, and hell even occupations- you get a serious tan when you work outside every day, so you can't make generalizations without a proper statistical survey. I do think there's a chance that there's some truth to what may have been a racial/eugenic component of the caste system as it existed in the ancient past and the topic deserves further statistical examination, but this would require a massive survey factoring in DNA and phenotype differences over caste lines.