I did not close this question, so I can only speculate about the motives of those who did. But this question reads very similar to a common rhetorical pattern you observe in many internet communities suffering from the filter bubble effect:
- Oversimplify the views of your opponents to a straw man.
- Point out contradictions in those oversimplified positions.
- Present it as a "gotcha" for how internally inconsistent the views of your political opponents are.
In this particular case, the question contains the following oversimplifications:
- Oversimplifying the "left-wing" position to "everyone on this planet is supposed to be completely equal", which ignores the distinction between equality and equity which is very important to many (not necessarily all) left-leaning ideologies.
- Oversimplifying the left-wing position of what exactly does and does not constitute cultural appropriation. Which is not nearly as undisputed among "left-wing people" as the question implies it to be. Is wearing clothes of a different culture always cultural appropriation? Some people might say that, but others hold more differentiated views and believe that context is very important to judge whether or not each specific case disrespects another culture or in fact shows respect.
- Lumping all "left leaning ideologies" together as having the exact same views on these two issues.
This strategy generally does not work very well in the context of a site like this, because the nature of the Q&A concept encourages to post contradictions instead of affirmations of such flawed premises. The comments and answers to the questions actually did a decent job at dismantling the premise of the question by explaining those misrepresentations.
Still, a lot of users react very negatively to people who appear to be using such a rhetorical strategy (whether or not they actually do is irrelevant for explaining this reaction, because the reactions of people are not based on the original intentions of the author, only on how they perceive them). So the downvotes and close-votes can be interpreted as an attempt to reduce the visibility of such rhetoric on this website.
Now we can of course argue if that's actually what should happen. After all, we can use such questions as an opportunity to educate people. And in this case this apparently worked, because the querent ended up accepting an answer which corrected some of these misconceptions about how people usually define cultural appropriation.