[ir123]

You define Hinduism as an ecosystem of ideas, with no clear boundaries, sometimes adopting ideas from Buddhism as well as other tribal rituals.

In another comment you said that casteism was brought by the West to India. (I do not agree with this but lets go with for now). So it clearly follows that Hindus (Hinduism) adopted casteism from somewhere externally. This is not for debate because we have seen and continue to see Hindus practicing casteism for whatever reason.

Hinduism can be simultaneously extolled for adopting "good" ideas from Buddhism but is also beyond criticism for adopting casteism from the west?

You arbitrarily laid the boundary for Hinduism at "caste" arguing that it was brought externally and hence not an inherent Hindu feature, yet somehow you take pride in Hinduism being a religion that does adopt external ideas. Which one is it?