Let me clarify it then. The poster I responded to claimed that Malthus is a butt joke of economics, which is patently false, and to support that, he cited Marx, whose economic theory is in fact a butt joke of economics. Is that clear now?
I can see what you've written, but I'm having trouble with the level of certainty you ascribe to what is surely a highly-subjective claim. It's not at all clear that Malthus is not (or hasn't been), at least partially, a "butt joke of economics", nor is it clear that Marxian economics' heterodox status today has any bearing on the quality of Marx's critique of Malthus.
Both Marx and Malthus have present-day adherents, though current positions have evolved well beyond those of their progenitors, but they've both also been widely panned. Obviously, the fact that neither mass global starvation nor global communism have overwhelmed humanity makes it easy to critique the pair, at least on a superficial level. You might suggest taking a more nuanced examination of their legacies, but I think that would reveal this entire discussion's lack of intelligibility. Perhaps you'd like to take a nuanced view of Malthus, but view Marx superficially?