No, this is not true. First of all, every nation is required by space law to publish the initial orbits of every object they launch, as part of that taking responsibility I mentioned earlier.
The US Government further publishes tracking on pretty much every single thing in orbit of the earth larger than a few centimeters, to help satellite operators avoid space debris. They do obfuscate the current orbit of their own spy satellites (only publishing their initial orbit), but other countries and even private citizens around the world keep obsessive tabs on these things (e.g. https://sattrackcam.blogspot.com/). This sort of thing is easily within the reach of even a medium sized nation state that was interested in the investment: just need a couple of big ole radars and you can do it just like the US does. So if you do try and hide the resources of a nation-state can easily counter.
The solution to oppressive government is not technological, it's political. Prevent countries from going bad, retrieve the ones that have gone bad, it works out a lot better for everyone.