I suspect that the author wants an anonymous VPS so that he has a computer that's not subject to physical seizure, e.g. TSA thugs grabbing it whilst entering or leaving the US. Plus the convenience of being able to access your VPS from anywhere you have a halfway trustworthy SSH connection.
You're thinking of Immigration and Customs Enforcement, which is in the Department of Homeland Security but is definitely not the TSA.
But anyway, they don't have the power to seize your US-based VPS as you cross the border. That would require an actual warrant which requires actual probable cause.
The author focuses on the US, UK, Australia, New Zealand, and Canada as the countries to avoid, but this seems crazy to me. The only common thread I can identify is that they all speak mainly English (sorry Quebec). There are lots of places I would avoid in addition to those; Iran, China, Syria, Libya, ... the list is nearly infinite.
Thank you for the correction, I said TSA when I meant DHS. I agree that they don't have the power to seize your VPS at the border: what I said is that they have the power to seize hardware that you have on your person, which is a non-trivial factor. They've proven themselves willing to abuse this power.
