First, we acknowledge that rights exist. I think that this is a fact that no one here would argue against. The question shifts to, "What is the nature of these rights?" I would take this down to either, "They are granted by the government," or, "They are inherent to all men by their very nature."
We will examine the first proposition. By this theory, it is the government (in our case, the people and their representatives) who establish rights. By this definition, rights are not necessary things- someone who lives in a government who does not permit certain actions does not have rights. If the people and/or government decide that people should not be able to do a certain thing, they do not have that right. Looking at things from this angle, men have a right to say what they wish and own guns simply because the people and/or government believe it is okay. In controverse, these rights can be taken away when the people and/or government decide that men should not have a right to free speech and to own guns to defend themselves. The same group that grants rights by definition has the ability to take away those very same rights.
Let's take the Second Amendment, for example. The Second Amendment was placed in the Constitution, recognizing the right of men to own firearms. This was recognized based upon the premise that men should be able to defend themselves against people and the government. Yet, if this is a right granted by the people and the government, then the very people we are to defend ourselves against can strip us of those rights, simply because the rights only exist by the people/government's assent, by your very argument.
Look at it this way- it is generally acknowledged that the Bill of Rights lists rights of individuals. Its purpose is to protect us from the government and the mob of majority opinion. Yet, you claim that these are the very things that grant these rights to us. As I said before, it logically follows that those who grant rights can take them away. It seems a bit paradoxical to assert that the framers of the Constitution acknowledged rights that protect people from other people and the government, and yet have those rights be removable by the very people they are meant to protect us from.
The other option is to view the rights mentioned in the Bill of Rights as existing inherently in all men, by our very natures. This proposition is not that every amendment is directly a God given right. Instead, each amendment procedes logically from premises which are in themselves rights inherent to all men. For example, God did not necessarily ordain that "All men should be able to own firearms." However, the concept that men should be able to own firearms follows logically from the premise that, "Men have the right to defend themselves." The right to a speedy trial proceeds from the premise that, "Men should not be forced to suffer unnecessarily," (I would assert that a prolonged trial IS unnecessary punishment). Even the religious clauses of the first amendment have basis in inherent rights of men, along with logical premises. "Men should have the right to worship as they choose while on earth," would be a premise based upon inherent rights, while, "Nationally established denominations restrict the ability of men to worship as they choose," is a logical premise. The two taken together add up to the clause in the First Amendment forbidding the establishment of a National Church while admitting free worship.
My point is that the rights recognized in the Bill of Rights, while not directly God-inspired, procede from moral premises which most men would recognize as true. The original premises are logic and rights inherent to men, and the propositions in the amendments follow necessarily, thus they are indirectly inherent to all men as well.
Granted, not all countries recognize certain rights which are recognized here. First, I would caution you to make a distinction between the granting of rights and the recognition of rights. Simply because in some countries men are forbidden to own firearms, which happen to be the only viable way to truly defend one's self in the modern world, does it follow that those men have no right to defend themselves? Simply because a country does not defend the right of citizens to a fair trial, does it follow that men are truly guilty of crimes when false evidence is brought forward against them? Simply because certain thoughts and ideas are prohibitted by a society, does it truly follow logically that those ideas are harmful to society at large, and that simply because those in power dislike something, it is wrong?
This all ties into this conversation. If the rights are inherent to all men by our very natures, it does not follow that the US can distinguish between who to grant these rights and who to deny them, as the US does not grant these rights at all. If the rights are inherent in all men, and the US chooses only to recognize them in citizens, but not in non-citizens, it is denying rights which by definition those people have by virtue of living, and thus is not truly advocating freedom.
Just food for thought.
You have provided much food for thought. Others here would do well to read it.