One of the basic refuge commitments is that one has to regard one who wears the ropes as a Sangha member. As Sangha members, they are part of the Refuge formula, ie the Sangha Refuge that is fit be offered offerings. By advising people not to offer to the Shar Gaden and Serpom monks, the Namgyal monks broke their own Pratimoksha commitments and all no longer pure Sangha and ironically, not fit to receive offerings; unless they repair their vows.
The above, does not every need to reason in the Protector practice. Just in basic Vinaya alone, it is wrong.