That is total balderdash. - Parents have total descretion over their minor's legal affairs, especially citizenship.
The one spouting balderdash is you.
From the nationality act of 1952 (which was in effect at the time):
From and after the effective date of this Act a person who is a national of the United States whether by birth or naturalization, shall lose his nationality by -- (1) obtaining naturalization in a foreign state upon his own application, upon an application filed in his behalf by a parent, or duly authorized agent, or through the naturalization of a parent having legal custody of such person: Provided, That nationality shall not be lost by any person under this section as the result of the naturalization of a parent or parents while such person is under the age of twenty-one years, or as the result of naturalization obtained on behalf of a person under twenty-one years of age by a parent, guardian, or duly authorized agent, unless such person shall fail to enter the United States to establish a permanent residence prior to his twenty-fifth birthday: ...." You can read the full text here:
http://tesibria.typepad.com/whats_your_evidence/1952_Immigration_and_Nationality_Act_66Statxx_TitleIII_Chapter3.pdf