I’d suggest that the writer of the CTD “first-timers blog” either get more informed about laws and legalities or stop trying to pass off bad advice. State laws, not federal, are the first place to gain understanding of where it is legal to carry. Some of the places cited do fall under federal law (post office, federal court house) but polling places are under state law control and those will vary. The closing sentence in the opening paragraph is really too broad brush to be helpful.
Good point, comments are allowed on their articles and from my experience there, they are very well received.
http://cheaperthandirt.com/blog/?p=21608#respond