But I don't think that, in a free country, the government should be monitoring people solely for their political views or what kind of books they read, without some actual evidence that they're a danger to anyone. Sure, maybe someone who buys an Ayn Rand book will eventually work to eliminate government, but I'm not sure owning The Fountainhead should land you on a watchlist; and the same should go for reading Proudhon or Kropotkin.
It's also really easy to run into false positives. In the '80s/'90s, for example, the police/media liked to paint a bunch of generally harmless BBSing kids as "dangerous anarchists" because they had an ASCII file of The Anarchist Cookbook—which is violent anarchist literature, after all.