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.