It does lead to "might makes it possible to do what the hell you want" but that doesn't mean that that is right. 10 minutes of medieval history tells you that that is exactly what happened in the past.
As your example illustrates, we know it is not right, and we have a common and instinctive urge to call it wrong. Thus, there is a human right that transcends government. It's wrong not just because a particular government says it's wrong, but because of something that is innate to humanity. (and I believe, the universe we exist in)
However that is academic.
What is the practical difference between protecting a right for someone and being the source of that right? If you protect someones right you can simply remove that protection. If the other isn't capable of protecting that right, what use is that right? If someone is raping you what protection is "It's my right not to be raped"?
No, it is not academic.
If you don't have the right to resist, why resist? If you don't have the right to free speech, why should you risk anything to speak against the majority/popular view?
Paying a heavy cost to assert a right is possible only when there is a concept of right and wrong that is more valuable than even one's own life.
Take away that ideal, and we are just bags of meat, and we are ultimately just slaves to the strongest bully in the neighborhood.
Another uncomfortable truth is that there isn't some magical protection on rights.
You speak of truth as if it were desirable, while attacking the concept of rights. ("it's not a right if someone isn't strong enough to protect it")
"It's not true if it's uncomfortable" - how much would you disagree with that?
Because that is wrong in the same way as "it's not a right if it's not protected by a government".
Most likely there is no god, and if there is He isn't doing much on this front. We have to protect the weak ourselves. For that we use governments.
Wrong. There is a God, and our instinctive desire for Justice, Right, and Protection of the Weak are strong evidence of His fingerprints.
We do need to protect the weak, and we are a part of governments - but governments are not the highest human authority - so we have the right to judge governments and force them to do what is right.