> "Opinion piece" objectively means "free bullshit zone".
I'm not a fan of Michael Shermer, but he claims SciAm demanded a complete revision of a column, and then later rejected one of his columns, right before getting rid of him entirely. So there's at least some rules about what opinions they're willing to publish, and that was under the previous editor-in-chief (as in the one before the one the article is about). The opinions that make it to press are curated, so if there's something off about them, the editors should be held responsible, and the op-eds don't have a different editor-in-chief than the main articles.
> Who even reads editorials in a science magazine?
I see no reason not to consider them as a significant part of the magazine's image. If the articles were all the same but the editorials were all written by, e.g. young earth creationists about their views, wouldn't what they put in that "free bullshit zone" shape your perception of the whole?