The most bizarre aspect is that the word
caste is of Portugese origin (casta - lineage, race, ethnicity) and there is no comparable word in Hinduism. Caste is a conflation of Jati (Birth) and Varna (qualities and karma) which are two very disparate concept. The former, Jati, is a living breathing practiced thing and the latter a conceptual framework that exists in texts which most Hindus never read or even hear of. See [1]. In India, Christians, Muslims and others like Jains practice Jati but it is often mistakenly conflated to them practicing Caste. This quote from the 1921 census of India by the British well summarizes it [2][3]:
"Middleton, one of the two Superintendents of Census operations of 1921, made eloquent remarks about the effect of the British Administration on caste in the Punjab. He observed, I had intended pointing out that there is a very wide revolt against the classification of occupational castes, that these castes have been largely manufactured and almost entirely preserved as separate castes by the British Government, our land records and official documents have added iron bonds to the old rigidity of caste. Caste in itself was rigid among the higher castes, but malleable amongst the lower. We pigeon-holed every one by caste, and if could not find a true caste for them, labelled them with the name of an hereditary occupation. We deplore the caste system and its effect on social and economic problems, but we are largely responsible for the system we deplore. Left to themselves such castes as Sonar (goldsmith) and Lohar (blacksmith) would rapidly disappear and no one would suffer . .. Government's passion for castes and pigeon-holes has led to crystallization of the caste system, which except amongst the aristocratic castes, was really very fluid under indigenous rule ... If the government would ignore caste it would gradually be replaced by something very different amongst the lower castes."
The key point to take away is "caste" was mobile at the lower strata but locked in at the top. I remember reading the Census of India in the 1990s and it had the same conclusion - as one ascended the economic ladder, the caste evolved too, which makes sense.
The British were the first one to categorize everyone into 4 castes which is map every Jati (Birth) into the 4 castes in some Hindu texts. The hierarchical & rigid classification of the 4 castes in India is a figment of the Western Mind. The 4 varnas exist in some Hindu texts as a conceptual formulation but Hinduism has hundreds of texts none of which is central unlike Judaism/Christianity or Islam who each have one central book. A practicing Hindu can choose to believe in any, some or no text sometimes within the same family. There are Hindus who eat meat and ones who foreswear it, Hindus who worship murtis (idols) and ones who are against it, Hindus who believe in a creator god (astika) and Hindus who don't (Nasktika) and so on and so forth. I know practicing Brahmins who will eat meat (and beef!) and non-practicing Hindus who are vegetarian. The variety is bewildering until you realize Hinduism is about seeking your own path. Most Hindu texts are ignored by the vast majority of Hindus and they are unaware of their existence let alone their contents.
There are temples today where priests are only drawn from Dalit "castes", which are the lowest castes. Even a few decades ago there were villages, especially in South India, where Brahmins could not go to Dalit neighborhood on fear of death and vice-versa. Jati is a complex practice that defies simplistic categorization and understanding.
You can infer the Jati of some one from their last name, the closest translation of Jati is Clan. Discrimination based on that is similar to discrimination based on Nationality, Ethnicity, Religion, Alma Mater or Fraternity. Idiotic and parochial. Should be condemned unequivocally. South Indian Reddy(s) who are often found in IT professions will as much discriminate against a Dalit "caste"" from Western India as they will against a farmer caste from Bihar in favor of their kind of castes. Again, stupid and parochial but similar to Japanese discriminating against Korean-Japanese or Han Chinese discriminating against Mongolians and Tibetans or Ivy Leaguers preferring other ivy leaguers, etc.
Conflating all the problems of discrimination in India to a 4-level hierarchy is just a imaginary and lurid construct of the Western mind.
[1] https://www.hinduamerican.org/wp-content/uploads/2019/12/Cas...
[2] https://www.google.com/books/edition/Welfare_of_Scheduled_Ca...
[3] https://twitter.com/BharatDharma/status/1162977793224802304/...