Article from the sisters' website on how/why they left the CMRI:
http://www.sistersofmarymotherofthechurch.org/67Reading the article, it seems that they have swallowed the Novus Ordo package hook, line, and sinker.
How could this happen? I see two clues in the article:
The election of Pope Benedict XVI strengthened their doubts and moved them closer to Rome. Within the CMRI convent, many of the sisters began to meet privately to discuss what they were thinking. They asked each other: after 40 years and no pope, had they been severely misled by Francis Schuckardt and the CMRI leaders? Some sedevacantists base their position on the supposition that the world will soon end. Like any millenarianist group, how long will they keep waiting after each predicted End of all Ends comes and goes?
Even the remaining CMRI sisters admit:
"We continue to pray for a true Holy Father. But we don't pretend to have in answer of how to resolve the question," says Mother Dominica. So much sedevacantist theology and philosophy revolves around the Pope, or lack thereof. I don't think any Catholics in history have spent as much time talking and writing and thinking about the Pope as sedes do. Sometimes it seems to me that sedes' entire faith hinges on that one issue. Everything else takes a back seat to it.
The other reason could be here:
To a sister, they credit the witness of the Missionaries of Charity as their strongest motivation to return to Rome. They saw in the MC sisters "so much charity, so much love, so much goodness;" says Sister Kathryn Joseph. "They won us over with their prayer and charity."Were these two elements lacking at the CMRI? Here is a warning for all of us. We certainly see among many traditionalists of all kinds, not only sedevacantists, an overemphasis on certain points of doctrine to the exclusion of other equally important points, and a falsely judgemental attitude towards others. Overcoming sin is a real struggle; if it were easy, we would all be saints already! No one is supposed to labor alone at that task. That's why Catholics, even those of religious vocation, live in communities. The desert hermit is the exception, not the rule. If we do not take care of each other, many of us will look for someone who will.
The world is seductive: if we trads don't supply each others' spiritual, emotional, and physical needs, some of us might turn to the world for these things. Our goal is to save souls, ours and others': just shrugging and saying "good riddance" to those who drop off the path from time to time is an act of uncharity that could backfire on us someday.