It's the path any "fighting from within" group will eventually have to take. I wrote about it here on the forum before but if you look at the history of the Roman Catholic church, there were plenty of groups who were trying to do the "fighting from within" stuff. The Galicians, people who were against the Counter-Reformation, etc.
What happened to all of them is that they either got condemned as heretics and persecuted, or they ended up capitulating to Rome and became irrelevant. If you also read about how the 2007 "union' (or takeover as I like to call it) occurred, people were panicking and saying "well how are we going to concelebrate with New Calendarists and be in communion with OCA, how will that work?!" and so on.
So they just did it. They went into communion with the MP, acted like it wasn't a big deal, and for most people, they said "oh, well they didn't make a big fuss out of it, so maybe we were overreacting."
The truth is that these people were primed to accept Ecumenism years ago. "Fighting from within" is a controlled opposition and the Ecumenist hierarchs want to keep these people around. Fr. Peter or others will give these speeches about why Ecumenism is terrible... at events hosted by the GOARCH where Elphidoros is sitting right in the front row.
Fr. Mikhail admitted in a video that he told he was to be made a priest after having only been in the ROCOR-MP for 6 months, and he came from low church Protestantism and by his own admission "didn't understand the priesthood... (due) to not having a great catechism", in other words, he knew nothing and they knew he would do whatever they told him to.
Fr. Methodius in Michigan talks about how one of the unfortunate things about Orthodoxy (though more prevalent in the WO) is that weak men who would never hold any worldly power can be promoted up the ranks really quickly, and serve as yes men to Bishops who have less than pure intentions.