I understand the point being made, but I think it's a very dogmatic, narrow view, and it conflates his opinion about what a "discipline" should be vs what the generally accepted norm is.
Obviously, physics and computer science are “disciplines”, but very few practitioners are aware of the history of their fields in a significant way. It’s a different type of endeavor.
You can do much of contemporary analytic philosophy without more than a cursory understanding of Ancient Greek philosophy.
There are experts in history of economics, including historical context and embedded within a sociological framework. The profession doesn't ignore that. It's just besides the point for much of what is of interest to current work. Mathematical modeling of macroeconomics doesn't depend on what Marx said about 19th century labor sociology in Britain. And even behavioral economics, which is all about how people actually think and behave (how how than why, but also a bit of why), doesn't depend much on why economics didn't think about things that way a hundred years ago, or what the society was like a hundred years ago.
I understand the claim that for something to be a discipline it has to have continuity and self-awareness (and criticism) about that. I'm not sure the claim is true, but even if it is, there is a difference between ‘every economist must do it’, and ‘someplace within the discipline someone is working on it’ (which is sufficient).