This misinterprets the data it presumably relies on (the Joint Committee on Taxation study of 1999 data) and, in any event, presents an incomplete picture. See JCT Study on 1999 Data.
First of all, from a procedural standpoint alone, without knowqing what fraction of the total income the group in question earns, it is impossible to tell whether 28% is progressive, regressive, or flat.
Secondly, page 3 of the above linked report (which is the relevant data since it includes almost all income and almost all taxes, indicates that the top 1% of taxpayers (beginning at $340,000 and averaging $1 million) earn 17.2% of total income and pay 23.2% of the taxes. Therefore, this article, which claims the top 1/2 of 1% pay $877B when the data shows the top 1% paid $391B has done a shoddy job of research---at best. It's calculations leave something to be desisered as well. If the $877B figure were correct, it would represnt closer to 50% of all taxes rather than 28%.
It doesn't say that. Your reading of the article is just more shoddy than the math you attribute to the author.... What it sez is:Simply put, a tiny group of people (553,380) were responsible for more than one-quarter of the income tax take of $877 billion. which if you do the math....877/4=219.25