If you actually believe your action on the internet cannot be monitored and reviewed, you're living in LA LA LAND.
Uncle Sam is everywhere and nowhere. If they want you, they will find you! While it is possible to confuse and distract what you're doing, the resources to remain completely fool-proof will cost you millions of dollars.
I mean think about it, the Government has capabilities to watch you in your own home while you're jerking-off. They have stuff that can see through almost all walls and roofs.
They've been able to create synthetic "humans" that act and speak like the real thing.
Yes, they have the means to monitor all computers, since most of the technology is from the USA.
Try saying no to the PENTAGON or NSA when they request you help your country. Either you comply, we steal it, we kill you, or we just destroy your company and put you in jail for child porn that just showed up on your computer.
Trust me most of the companies just comply, and then deny everything in public.
Also remember, the best cyber crooks work for the Government, just like the most successful drug dealers have Government liaisons.