No, it is not. Unless of course you believe that you have no sefl ownership and that only a government can grant you a right to anything. Which it is obvious that you do.
So I'll ask, someone who built a house on a vacant plot and began tilling it for agriculture, do they own the house and land of their labor? If someone shows up one day and says "hey! This is now my land!" Does the person who showed up have any moral or ethical grounds to acquire the property by force? If the second man kills the first, even without a government to come and take him in, was his murder ethical? Is it still murder even without a government to punish this person?
The answer is obvious.
This works the same way under contract. If Joe owned land and voluntarily agreed to sell it to Tom via contract, does Tim have the right to lay claim to the land? Of course not. Morals and ethics are not derived from governments, Corky. They are rules of nature and the right of man to own himself and his labor.
Now, if Tim shows up to take the land from Tom by force and began shooting at Tom, and Tom killed Tim. Was Tim's use of defense ethical and moral? Of course it is. As Tim initiated violence against Tom who already made a peacefull exchange.
Just admit you're a government loving LOLberal and lets move on. You know nothing of the ethical and moral implications of libertarians. Which is the foundation of most principles. Only a boot licker who requires a ruler would deem government the owner and arbiter of all land.