Idolatry is worshiping false objects, objects other than God. The Divine Liturgy (Holy Mass) is entrely focused on worshiping the Triune God. Is the manner of worship now made idolatrous becase John Knox says it is? If so, then the muscial instruments in the Presbyterian churches are idolatrous innovations as well, for any kind of instrumental music was originally banned by the Reformers. And so are microphones and visual aides, because none fo these are mentioned in the Bible.
I think it would be good for the Protestants to look for logs in their own eyes before they busy themselves finiding thorns in other churches. For starters, they can show us where does the bible say that divorce is somehting Christians can exercise freely? Does it ever occur to the Protestants that perhaps they do many things that are not scripturally sound?
Divorce, especially with a remarriage is a sin & I don't know that any Protestant denomination teaches otherwise. Most Protestant denominations don't teach that it is an unforgivable sin (tho some do).
The hardness of heart that preceeds divorce is the actual sin & a divorce "outs" the sin that has been going on in private. "Because Moses by reason of the hardness of your heart permitted you to put away your wives: but from the beginning it was not so." Did Moses create divorce or was divorce given to Moses by God? A marriage without God at its center is not as God intended & a society where divorce is on the rise is one where too few understand what God wants for us in our marriages, as we've begun to think that it is all about us.