That teach Sunday School bit was the same pablum that Hillary Clinton used to trot out, if those folks are teaching Sunday School, Lord help us all.
Yes, the mainline Presbyterian church is a church in name only. One can be ordained a minister in the denomination without having to believe in the Bible. It’s sad.
There are some Bible-believing Presbyterian denominations, though, so remember that when you hear the MSM talk about Presbyterians. They’re not all the same.