[Tomte]

I find your counter-argument against rem units very weak.

What are cross browser concerns here? Why should he even mention the possibility that someone might "fix" an elements font-size? Sure, the author doesn't explain all of CSS and all of UX/UI in an article focussed on a single issue. That's not a mistake.

Your px recommendation is... strange. The article is one of those "newer" CSS articles that care a lot about responsiveness. You seem not to care. Fine, but I guess you're in the minority there.

Your insult against front-end developers (in both your comments!) is simply childish, and frankly, it seems you just have an axe to grind with the author(s).