None of that is true.
From the Tripoli Safety Code, NAR is no different.--
Tripoli allows certified members, as well as certified NAR members, to attend our launches and safely launch rockets that are "made of paper, wood, fiberglass, or plastic." Their rockets may also be made of a "minimum amount of metallic parts" in whatsoever percentages "necessary for airframe integrity dependent upon the installed total impulse, and whose primary use is for purposes of education, recreation, and sporting activities." Whatever material is used in the rocket’s construction, the rocket and materials must conform "to the other requirements" of the Safety Code. Undergirding and overarching all of this, "a high power rocket shall be constructed in such a manner and with suitable materials to withstand the operating stresses and retain structural integrity under conditions expected or known to be encountered in flight." For the purposes of this policy, the flight includes placement on the launch pad, the launch sequence, flight to apogee, descent, and landing. The practice of constructing a rocket to withstand "operating stresses and retain structural integrity" while anticipating possible unknown conditions is not discouraged.