I think Roy has his causation backwards here.  Mainsteam
economic "science" is hostile to contextual thinking of most any
kind because it is professionally invested in a scientistic
use of formal models and statistics.  History of economic thought
is contextual thinking at its core -- and so economists
have effectively eliminated it from their curriculum.  To the
extent that genuine science is dependent for its improvement and
advance on a growing contextual understanding of its problems,
"mainstream" economics was not interested in doing actual science.

So I think you have to begin with the fact that in the first instance
economists are not interested in genuine scientific work, or real science
progress.  (If you must, you might argue that mainstream economists are
interested in a sort of fake science, a cargo cult science which tries its
best to imitate some parts of real science -- but this activity should not
be confused with genuine science.)

For the "mainstreamers", the hostility to the contextual thinking embodied in
the history of economic thought came first -- and what followed was a
contempt for any sort of contextual research the mainstream associated with this
field, e.g. all of the various "heterodox" brands of economics.  Stuff the
mainstreamers view as just waste-of-time "history of economic thought".

Greg Ransom