Stack Exchange (or, at least, MSE) has the interesting phenomenon that people often demand for downvotes to have an accompanying justification.
However, I don't see this on other sites I visit with a up/down ratings system. Occasionally people might ask why something gets downvoted, but there is rarely a sense that they are entitled to a justification, and even more rarely does peer pressure favor such entitlement.
I see pushback against downvotes, of course, it just doesn't manifest in this form.
(admittedly, I do not widely participate in social media, so my perception may not reflect the norm)
So what is different about this site gives people the idea that they are entitled to an explanation for a downvote? Is there good reason for that opinion? Is it just something that some early adopters did and it turned into a SE-local meme? Something else?