Although I disagree with ilyenkov on the specific use of "evil" because I think we should just use the term for egregious shit without fear of being mistaken for religious positions, I think this relativity it absolutely not "it's all relative dude" but an understanding that the only absolute is between relativity. As analogy, location in space is relative; there is no way to say where something is without relation to another. That relation itself is absolute and can be the basis of a metaphysics much more complex than the dudebro shit. This is what made Hegel revolutionary in his thinking and Marx after. Keeping that analogy going, you can do the same thing with speeds: only meaningful relative to another but that relativity gives MORE clarity about speed than trying to analyze it alone. In fact, talking about speed without a reference frame can only cause you to miss the beauty of physics! It also makes acceleration uniquely interesting in it's absoluteness, because it's speed relative to speed WITHIN THE SAME OBJECT.

Marx loved this shit, the lovable nerdy shithead, and wanted to apply as rigorous of thinking to society possible with the help of the natural sciences which had such realizations. "Relative" in it's vulgar form is dumb and only leads to inconclusive positions.

Maybe that was what you meant by your joke but don't want a passerby to think we're vulgar about this