Structuralism can mean different things based on the context, I think the post you're replying to is meaning Structuralism in the philosophical context, but I think the post they're replying to is meaning it in the literary context (which derives from the philosophical), while the author of the post you're replying to seems to think they(the original poster) are somehow referring to structural Racism, which that interpretation of the primary poster does not make sense to me (hence my saying I think they mean Literary structuralism)

So structuralism in literary theory is that the structure of a text is the important thing which can end up being a lot like those articles you see every now and then "There are only 10 basic plots in the world, here they are" or some stuff like that (I obviously say this as someone who does not much care for structuralism so take my words with a giant grain of salt)

on edit: clarification

> You're not using the terms "structuralism" and "post-structuralism" correctly.

The first sentence is the important part. "Structuralism" is in no way related to "structural" or "institutional" racism. "Structuralism" is what the next sentences are describing, and it doesn't matter if you understand them; they were probably added as ample evidence that the first sentence was true, and possibly as stuff to google if you're interested in a subject completely unrelated to this discussion about the article.

Structuralism is some French theories about how creative writing should be structured.