This article makes some bold, false claims. What is true is that Tailwind will generally result in a bigger stylesheet over the wire than if you hand-write CSS. That's a well understood trade-off, made in exchange for several benefits.
But then the article suggests that every claimed benefit of Tailwind actually doesn't exist, and that Tailwind is in fact worse on all fronts. He seems genuinely to believe that there is no merit in Tailwind's huge success at all, that it must entirely be explained as arbitrary flocking behaviour. What idiots we must be, going to all this effort to write bulkier CSS, more slowly, with less flexibility! I have to guess that the author has not given it a fair trial (i.e. using it on a real project in earnest) before coming to his conclusions, nor had any good conversations with old-timer CSS experts who love CSS and love Tailwind. He's jumped to the conclusion it's a thing noobs like because they find CSS too hard.
I made a similar assumption at first, that Tailwind was just another horrible "CSS-in-JS" type thing, which I always felt were for front-end newbies who were so reluctant to just learn how CSS works that they'd be seduced by shiny packaging and use horrible JS contortions to 'shield' themselves from inheritence and cascading (which are actually useful, powerful aspects of CSS when understood).
But then I started to notice its hype cycle felt different, that even a few old school traditionalists seemed hooked on it, and I tried it out in earnest on a project. And I soon realised it's a very rare thing: a real innovation in front end, the kind that comes along every 5-10 years, up there with the component paradigm. It's not another CSS-in-JS thing at all. With Tailwind, you are writing CSS, in a very real sense. And thus your success with it is highly correlated by how well you can write CSS by hand – it is not an alternative to learning CSS; it is an extra, more advanced thing you should learn after learning how to do handwritten CSS well. What it brings is a beautifully designed build layer that justifies its own existence better than any other build layer I have seen 20 years of front end development. It gives you a massive net reduction in 'indirection', letting you style things right where they are. And it reimagines style 'reusability' in a way that (to be as succinct as I can) prevents your styles ossifying your DOM structure too early during the creative styling process. These are some of the reasons why Tailwind has blazed through the industry the way it has. Not because we don't understand CSS and want to avoid it, but because we want to write more of it, quicker and more flexibily.