Am I right that your objection is "The articles
wholly unsuitable for inclusion in wikipedia under the titles they
have on that site."
I've yet to see anyone disagree with you on
That might be a diplomatic way to approach them--just say that
all of their stuff is welcome, if titled "Marxist views on X..."
or similar, and that some information from those articles might
also make its way into the "X..." articles themselves, but not
most of it.
I would not be in favor of having loads of articles on someone's view on
something. We need a general article on Marxism, and 2 or 3 articles like
"Marxist views on Economics" or "Marxist views on History" might even
ok, but in general such a view should be (with the clear indications what
it is) on the main page in those areas where the Marxist view is important,
and not on Wikipedia at all where it is not.