Ironically, the best reason I can think of to own an assault weapon is to protect myself from those who would confiscate it. The efforts of our government to strip the citizens of this country of their right to protect themselves is against everything for which our founding fathers stood and sacrificed. Politicians would prefer we rely on government rather than take responsibility for our own safety.
In a free society, the individual has the right to engage in any activity which does not infringe upon the rights of another, unduly emperil him, cause him harm or deprive him of his property. Our Constitution granted government the power and obligation to ensure that freedom and it gave individuals the power and obligation to enforce that covenant by its guarantee of a well armed citizenry. Today, with the complicity of an apathetic public and under the guise of public safety and welfare, an all too powerful government is abridging citizen's right to bear arms. The covenant is no longer enforceable by the people.
Sadly, those who have been in power during the last century have incessantly eroded the provisions of the Constitution to the point the only rights we have left are those for which we, as individuals, are willing to fight and die.
I own a handgun. I own an assault weapon. When I die, I will still own those weapons. If, in the interim, the government decides to deprive me of that right, it will have to pry those weapons' red hot barrels from my cold, dead fingers.
It is not a matter of hating government. It is a matter of loving liberty.