I agree. If you conclude that the Dimond brothers are frauds, then to be fair, you have to say the same about the SSPX, the SSPV, the CMRI, and all the traditional Catholic religious groups. People only call the Dimond brothers frauds but never question the other groups which are no more legitimate.
That's not quite the same situation. SSPX, SSPV and CMRI communities stem from apostolic succession because they originated from Archbishop Lefebvre, notwithstanding their subsequent religious communities lacking official Church approbation. The Dimond's monastery does not stem from any community directly linked to +Lefebvre or subsequent groups - such as SSPV and CMRI and independents - who broke from +Lefebvre, nor do the Dimond's community stem from any pre-Vatican II Church sanctioned community. The Dimond's monastery essentially just "set up shop" with no lineage to a validly ordained bishop, priest or consecrated monk. The founder of MHFM reportedly never even took vows while he was a lay postulant at another monastery before he left it and founded MHFM. Conversely, the SSPX, CMRI and SSPV have communities that are established by actual clerics who were conferred Holy Orders by bishops with apostolic succession.