“While I love a good critique of wealth accumulation and inequity, this song is not one; in fact, it is deeply racist.” = This song is racist.
“So why shit on black folks? Why shit on rappers? […] I’m gonna take a guess: racism.” = To me that seems like a pretty clear statement that it’s the artist’s racism, i.e. the artist is a racist, but if you have an alternate explanation for whose racism the author is referring to, I’m all ears.
“She apparently calls herself a feminist – let’s just hope her feminism gets a lot less racist as she develops as an artist.” = The artist’s beliefs are racist. Again, to me that doesn’t seem any different from asserting that the artist herself is racist – who else has racist beliefs? – but perhaps you have another explanation.
Coincidence is your word, not mine. My opinion is that the history of these terms is beside the point.
For example, I recently learned that “fiasco” literally means flask, and we call a screw-up a fiasco because when a glassblower messed up a potential masterpiece, they’d wrap it up to hide the flaws and sell it as a common bottle or flask. Interesting! However, this doesn’t mean that referring to something as a fiasco is demeaning to glassblowers (even shoddy ones). The etymology is fun to think about, but it has little effect on people’s use of the word.
This analogy would work better with the roles reversed: you show up to a lecture hall and hear someone explaining that gremlins are behind gravity. Some of what he’s saying makes sense, kind of, but it seems like he’s skipping over a few things you know about gravity that aren’t gremlin-related. You look up his other work, and it turns out he thinks gremlins are also behind magnetism, earthquakes, fibromyalgia, and the disappearance of flight MH370. You would hopefully conclude that he’s obsessed with gremlins and is cherry-picking evidence to fit his theory, and not that gremlins really are everywhere.
These accusations of sexism/racism/etc in cultural artifacts would be more convincing if they didn’t come over and over from the same critics who, oddly enough, just happen to detect sexism/racism/etc in nearly everything they come across, and just happen to hold the political belief that sexism/racism/etc permeates every aspect of our culture. Their beliefs precede and shape their interpretation of culture.