Having a technical editor is key (like companies in this article), and not editing too much. I’m non-technical and have edited drafts of engineering blog posts too much and lost favor with engineers who contribute.
Once I restored that favor, I would have lost it again if I told contributors, hey, we’re going to share your draft with a bunch of your mates (like companies in this article). That’s groupthink and it brings any blogging momentum to a standstill.
It's certainly possible to over-edit pieces and lose the original writer's voice because the tone or whatever is different from the editor's preference even though it's not wrong.
That said, for any company blog that has an editor, I expect there to be some style guidelines that posts/articles at least roughly stick to and, if the editor doesn't feel they're enough of a subject matter expert in the topic to provide at least a cursory review, they'll probably send it to someone who is if the writer hasn't already done so.
If it's purely a personal blog, that's something else but my observation is that, at least larger, companies have generally moved away from hosting individual blogs on company properties. The degree to which they're OK with people posting on their own sites I'm sure varies by company.
Once I restored that favor, I would have lost it again if I told contributors, hey, we’re going to share your draft with a bunch of your mates (like companies in this article). That’s groupthink and it brings any blogging momentum to a standstill.