Letters during his monastics community seem to point out that Fr Seraphim Rose thought the Matthewites were overzealous.
The “Mathewites” preach absolute “strictness”: since 1924 all New Calendarists and all those in communion with them are without grace; hence the “crisis” which caused Bp. Mathew to consecrate successors by himself—he and his followers believed that he was then the only Orthodox bishop remaining in the world. It is therefore astonishing that they could have been persuaded to have any contact with our Church at all, as at the Sobor of 1971, and Dr. Kalomiros tells us that this was because Fr. Panteleimon of Boston told them that our bishops had “repented” and now were willing to accept the Mathewite position. Once they saw that this was not so, the Mathewites resumed their attacks on our Church, and the last we heard they were almost resolved to give our Church over to anathema.
What do the Matthewites think of this letter? While it does condemn the heresy of ecumenism and the MP, it seems to critiques the Matthewites position.
Link: http://nftu.net/wp-content/uploads/2017 ... alotry.pdf