Of course we are free to do that, and in fact you can easily find such comments on Western forums, whole subreddits full with such drivel and even specialized forums just for that. It's called freedom of speech and is one of the basic rights in liberal democratic societies, as opposed to totalitarian societies (be they communist, fascist or theocratic).

I am, yes. Why?

Yes

Yes. Read HN for a bit, you'll find plenty of anti-capitalist and anti-NATO statements. The police don't show up for the authors. The posts are often downvoted, though - not because they're anti-sacred-cow, but because they're usually shallow propaganda talking points, with no thought or substance.