I've only skimmed this thread, so apologies if this has already been addressed, but this isn't how it works. Interdiction =/= excommunication, and is not a full on suspension of religious life. From wikipedia (which is basically consistent with what the Catholic Encylopaedia has to say on the subject, but using much simpler language) -
"A local interdict forbade in general the public celebration of sacred rites. Exceptions were made for the dying, and local interdicts were almost entirely suspended on five feasts of the year: Christmas Day, Easter Sunday, Pentecost, Corpus Christi and the feast of the Assumption of Mary. Besides, in the case of a general local interdict, it remained permissible to celebrate in the cathedral or the only church in a town, but without any solemnity such as the ringing of bells and the playing of music, Mass, baptism, confession, and marriage."
Interdiction is the church working to rule, not going on strike - basically doing the absolute minimum to minister to souls (except on the high holy days mentioned above), but putting a ban on the "fun" stuff - bells, music, and so on. Doubtless also any sermons that were delivered would also dwell heavily on the moral turpitude of the ruler who had brought this state of affairs about.
OTL, the English church mostly followed John's lead - one of the reasons why he was able to hold out for five years in the first place
Interdiction wasn't an attack on the rulers civil authority, it was an attempt to force him to recognise the church's spiritual authority. Any priest who attempted to raise a peasant's revolt would be treated as a traitor (unless the king had done something *really* counterproductive, like, well, convert to Islam).