the writer noted what he called (something like) "dangerous hardline Marxism" (or somesuch) that he believes has taken root in a few European countries.

Not surprising. They are the spiritual (maybe no only spiritual :)) descendants of various hardcore trotskites, so adamant in their "proper understanding" that they were completely ineffective because of intense factionalism (thanks God for small mercies). Anyway they survived in the west, in the east they were properly disposed of ;)
And they still spread their gospel...