I don't really agree with this. Marxism has a clear political goal, which is the emancipation of the working class. It isn't depoliticized in the way biology or physics is in liberal society. If Marxism was truly depoliticized like this, there would be absolutely no reason why the ruling class would be so hostile to Marxist text. This would be like if the ruling class started banning books on string theory, comparative linguistics, or non-Newtonian fluids. The closest amount of hostility directed at scientific text is The Origin of Species and even then, that's mostly confined to the US.

I think the OP made an error in considering science as practiced in liberal society when liberalism is all about siloing and atomizing everything in existence until every single thing in existence, whether it's people or fields of study, exists in its own self-contained bubble. Why shouldn't our scientific pursuits be informed by our ethical and moral considerations? Science isn't the pursuit of knowledge for its own sake. That pursuit has to be tempered by how it would benefit society as well as be informed by societal ethics and morality. No, we shouldn't fund or even have experiments that determine how high cows can be dropped from and still survive.