Most of the discussion here centers on how linguistic commitments ought to drive decision making in determining the Unicode spec. It's already been covered how Unicode provides a number to symbol (i.e. codepoint) mapping; composition, rendering, input, etc. is left to the system implementation to determine.
I actually worked with Lee Collins (he was my manager) and a whole bunch of the ITG crew at Apple in the early 00's. The critique that this was just a bunch of white dudes that only loved their own mother tongues but studied other languages dispassionately as a superficial proof of their right to determine an international encoding spec is, to me, misinformed, and DEEPLY offensive.
I had just gotten out of college and it was AMAZING to see how much these people loved language! Like it was almost weird. Our department had a very diverse linguistic background and, oftentimes, when you had a question about a specific language property you could just go down the hall and just ask "Is this the way it should be?"
All the discussion here happened on the unicode mailing lists as well as in passing at lunch and at team meetings. Lots of people felt VERY passionately about particular things; I just liked watching the drama. But to write an article like this that somehow intimates that people didn't care is wrong. People cared A LOT.
It's been touched in a couple of comments, but a big factor in Unicode was also the commercial viability of certain decisions. You have Apple, Adobe, Microsoft, etc with all of their previous attempts at internationalization/localization. If you wanted these large companies to adopt a new standard you had to give them a relative easy pathway to conversion and adoption.
I think the article, in general, lacks a perspective that dismisses the work of the Unicode team as well as the different stakeholders. Historically, accessible computing was birthed in the United States. The tools and processes are naturally Ameri-centric. I'm not saying it's right, I'm just saying it is. The fact that the original contributors to Unicode were (mostly?) American shouldn't be a surprise; they had the most at stake in creating interoperable systems that spanned linguistic boundaries.
http://www.unicode.org/history/earlyyears.html
A purely academic solution may have been better. That's not certain. But it's pretty clear that any solution that didn't address the needs of pre-existing commercial systems would never be adopted. I'm surprised this hasn't been emphasized more.
I have more thoughts on how to solve the problem that the author complains about but I'll leave that for another day.