[saltcured]

I would read it as there being a different threshold for what is citation-worthy versus presumed background knowledge.

Imagine if every graphics paper had to cite every concept they use from arithmetic, trigonometry, and linear algebra textbooks...

[zozbot234]

This was citation worthy because it's new knowledge to the field. Even in a graphics paper, you can cite whatever basic techniques you're using if it's not clear that everyone will be familiar with them.