Why isn't triangulate points (for any arbitrary number of views and not just two views) part of the official opencv python bindings?

no, those were never “official” (they never maintained pip bindings in the past). however, this is unrelated to your problem.

where did you find this ?
https://docs.opencv.org/master/d9/d0c/group__calib3d.html#gad3fc9a0c82b08df034234979960b778c