Anyone arguing this doesn't understand the basic structure of the debt held by each country.
Greece's debt was in Euros, which they couldn't just print more of. Our debt is in dollars, which we can.
If we ever get to a really terrible Debt to GDP ratio, we can print our way out of it. Greece couldn't (nor Iceland, leading to bankruptcy). State and local governments can't.
The logical result of this is inflation.
Thus I'd worry more about inflation, which you can protect yourself against and hedge against, than government spending, something out of your control. Worry about what you can control, not what you can't.
(My apologies if this was covered in the article. I skimmed the first page, but wasn't interested in reading four pages of fear mongering.)