WOW, in reading your post it sounded like my case all over again. Except I was attending meetings up until my ex left me and my 16 year old daughter. Her father was likewise the PO, whole family witnesses, I disagree with your statement here that they were all very "spiritual", I prefer to use the term very organizational, a spiritural person doesn't do what they do. To answer your question why would they treat you in such a way? Take a look at the Bible example, I may be wrong but I believe the only persons who ever stood up against family in the Bible and chose to follow the course of right in the face of family, was Korah's sons. Even King David chose Absolom over what is right. 2nd Samuel 19:1-7 says
1 Later it was reported to Jo´ab: “Look! The king is weeping, and he carries on mourning over Ab´sa·lom.” 2 So the salvation on that day came to be an occasion of mourning on the part of all the people, because the people heard say on that day: “The king has felt hurt over his son.” 3 And the people began to steal away on that day to come into the city, just as the people would steal away when they felt disgraced because they fled in the battle. 4 And the king himself covered up his face, and the king continued crying out with a loud voice: “My son Ab´sa·lom! Ab´sa·lom my son, my son!”
5 Finally Jo´ab came in to the king at the house and said: “You have today put to shame the face of all your servants, the ones providing escape for your soul today and for the soul of your sons and your daughters and the soul of your wives and the soul of your concubines, 6 by loving those hating you and by hating those loving you; for you have reported today that chiefs and servants are nothing to you, because I well know today that if only Ab´sa·lom were alive and all of us others were today dead, why, in that case it would be right in your eyes. 7 And now rise up, go out and speak straight to the heart of your servants, because, by Jehovah, I do swear that, in case you are not going out, not a man will lodge with you tonight; and this will certainly be worse for you than all the injury that has come upon you from your youth until now.”
As the scriptures says "Don't mock me, you will reap what you have sown".
That is why Christ said we must love him more than our families. My ex's family did the same, she filed for the divorce, changed her name in the first week, refused any contact with me even for financial matters, she was exonerated, my daughter and I were DF'd, eight months later when I moved on with my life with my present wife. They THINK they got away with it but the scriptures will bear different in the end. I now feel sorry for all of them, I pray that Jah forgives them and blesses them. I thanks Jah for getting me out of the situation and seeing the light and I now have a wife who does love me. Don't feel bad, you cannot change what you cannot change, and people is something that you cannot change. Embrace a new relationship with Jah and realize that people, an org of people did this, not God, he hates the divorce. Imagine how he feels, your ex divorced Him also, and he truly didn't do anything wrong. Take courage in the words of Is 41:10,13 10
Don’t be afraid, for I am with you.
Don’t be discouraged, for I am your God. I will strengthen you and help you.
I will hold you up with my victorious right hand.
13 For I hold you by your right hand—
I, the L ord your God.
And I say to you,
‘Don’t be afraid. I am here to help you.
ABR