No, this is not accurate. And your chances of finding an expert on Marxism that isn't at best a closeted Marxist are basically nil due to the immensely complex history and depth. Probably the most arms-length analysis you'll find are from guys like Chomsky.
Marxists are largely academics, and those forums are largely comprised of professors and professional scholars. They aren't bootlicking morons like Nazi's who still idolize Hitler, a man who really didn't have an actual ideology and admitted as much (see: his economic philosophy of not having an economic philosophy).
There is a subset of the leftist community that is similar in this way in that they support Stalin and glorify the USSR (they are called "tankies" within Marxist communities), but such is not the standard. Peer review is actually very, very strong in the Marxist community and has been since long before the Bolshevik revolution, when the left communists criticized Leninism (correctly in retrospect) for being too centralized and domestic, to the famous divide between Trotsky and Stalin, to the fervent market of Marxist criticism of the USSR during the height of the Cold War, to the Western division of Marxists with regard to criticism of Soviet imperialism, to the current discussions on the theories and contradictions of Trotsky and Mao in new wave organizational models.
Because it is not a homogeneous ideology and it is without historical or partisan allegiances, you can get the very best information indeed (at least in the areas of overlap). That is perhaps the best and most annoying thing about a Marxist: they won't let a disputable interpretation or recitation go unchallenged. It makes for vivacious and nuanced academia, but absolutely horrible political organization.