This article is just so subjective. If you have 5 plugins that you constantly use together, having them in one repo is not bad. Especially if they are plugins that YOU maintain.

"They are their own entities and needs to be separated. Keeping them locked up together makes it impossible to share code across projects. It is the way Git is supposed to work, it is the way Composer is supposed to work, and it is even the way WordPress itself works."

If you use the same 5 plugins across your projects, its more efficient to bundle them and your bundle becomes your "entity".

Additionally, I think there's nothing wrong with having your entire wp-content as a repo. Ideally, you would only have the theme and plugins you're working with, and media that's on the site, although you could argue that 'uploads' should be it's own repo.

Also, WordPress bundles several things that are their own repositories. So the argument that WordPress works that way is moot.

I also think it ruins innovation to say "You can't do it that way because that way isn't the way it's 'supposed' to be done." How different would life be if we always stayed inside the 'intended' lines of something. You can use Git anyway that fits your needs. Adapting your workflow to someone else and their ideals isn't ideal.

Use technology to your benefit. Even if others scorn you for it.