Well then
I don't accept that the powerful get to define Christianity because of their power.
The Cathars (for example) regarded themselves as good Christians. My Christianity is rooted in large part in the views of those who considered themselves Christians and who were considered as heretics by others (Pelagius, Spong). I don't accept that the abscence of power on either their or my part reduces my or their Christianity.
For my part as a Christian - the answer to the op from my perspective is clear.
If you wish to demote me from my Christianity then I contest your right to do so or the view that your opinion regarding my bona fides as a Christian is superior to my own.
To my mind Christianity lies in following Jesus, trying to be like him. It means Tolstoy, Spong, Newell, Pelagius and others.
It means God is the Ground of All Being and a Mystery.
Listening to the institutional churches voice echoing across history all we can know is what the big boys with the sticks said. Tolstoy argues that they weren't Christians at all (he presents a good argument in my view).
There is another quieter voice alongside it to which I argue it is equally legitimate to attend.