Probably it resonates with someone's superficial experience using LaTeX, but the arguments it uses stem from analyzing just the beginning of a document, which is naturally full of boilerplate that you don't usually encounter in the body of your work, and perhaps from a badly chosen color scheme in the author's text editor.
The author is very quick to dismiss the whole idea of separating text and presentation showing how easier it is to just use a WYSIWYG editor. They don't hint at the hassle to eventually refactor your text, to give a uniform style to excerpts you incorporate from other sources, to adapt your formatting to different publishers' guidelines, etc.
And finally, the author decided to omit talking about maths all together. Not only how to write and display formulas, but also all the environment around it, like equations (and how to refer to them), theorems and proofs, etc.
No matter how you feel about LaTeX, this article doesn't dive into any of the features it's famous for.
My personal take about LaTeX? Don't consider it for short, simple essays. Writing a full book, several chapters, sections and subsections, non-negligible bibliography, maybe with some math in it... that's a job for LaTeX!