So, yeah, the whole thing sounds terrible. The nature of denominations such as yours is that there inevitably will always be endless issues like this that crop up ever so often. I mean anywhere people are there will be problems- but the very organizational model matters and can often set up a situation where things such as you described can occur. It's due to the fact that the entire service generally centers around the preaching of a sermon. Sermons, being relatively subjective in their content, are more like speeches and the person that gets to preach generally has a lot of free reign to spread their own interpretations and ideas- even of a political nature.

Liturgical churches revolve around the Eucharist, which is 100% centered on Christ. There are epistle and gospel readings that are standardized for certain weeks on the church calendar and the homily revolves around the scripture readings. All of it is designed to keep the focus on Jesus Christ. Not to say some people don't try to find ways to start controversies- even in liturgical churches (they do)- but such things seem to happen at a less frequent rate.

Again, I'm sorry your family had to go through all of that. A lot of us are no strangers to shenanigans of that nature in churches like yours. It's the same song, different verse, so to speak.