The author of the original article doesn't quite understand this point.
A blog post by (right-wing) Harvard professor Greg Mankiw clearly explains this: http://gregmankiw.blogspot.com/2008/10/blog-post.html
Sure, I'll agree that the percent of your net income that is spent on necessities is continually decreased as your income increases. This is definitely true.
I'll go one step further and say that taxes probably don't largely effect human behavior. If I have worked hard enough to earn $250k/year, it's due to some intrinsic motivation, not the benefits of that salary in the US tax code.
However, if America was built on encouraging the masses to converge on an average income, then it wouldn't be America at all. This country stands above the rest because of its tremendous wealth. It's built on incentives of self-interest. It's the ability to create unbound wealth that attracts the most brilliant minds to this country, and everybody else reaps the benefits. We should be encouraging these people to work, not take a vacation because added tax pressures are further reducing the value of their work.
This is particular relevant to the entrepreneurial crowd of Hacker News; entrepreneurs are, after all, responsible for 0.2% of the country's input and 17% of its output.
I don't believe that people change their work habit, or choose to work less, just because of a relative tax increase. However, they may be more inclined to find more tax efficient schemes.
You're thinking of it from the wrong side.
You want these people to work hard and long because they're good at what they do.
You benefit from their work. You don't benefit as much from their vacation.
Most people won't change their habits, but it is always the marginal earner who has to decide Do I work x% harder for x% less money?