After researching Wikipedia and other on-line sources, I found an article that gives a Reformed Protestant view of Progressive Christianity.
Here is an extract from an article written by Dr. Michael J. Kruger (Ph.D., University of Edinburgh) who is President and the Samuel C. Patterson Professor of New Testament and Early Christianity at Reformed Theological Seminary in Charlotte, NC.
Progressive Christianity has a low view of Christ:
One of the hallmarks of progressive Christianity is the way they view Jesus. The orthodox view of Jesus, of course, is that he’s the divine Son of God and worthy of our worship and worthy of our adoration and to be praised as God. But, of course, that’s not what progressive Christians believe. They believe that Jesus isn’t so much the divine Son of God, but rather just a moral example for us to follow. Jesus is more of a big brother that sets a pattern that we walk in his footsteps. That’s partly true, of course, we do follow Jesus’s example, but progressive Christians make that the main thing. Jesus is just a picture of what we can be and what we can do and his main point is just to set an example for us. The lowering of Jesus is the first mark of progressive Christianity.
Progressive Christianity is focused on moralism, not salvation:
Tightly tied to that is this big focus on moralism. If you don’t have any sort of sense of Jesus as someone to be worshiped, then he’s just someone to be emulated, so the highest goal of the Christian life for progressive Christianity is that you just have to be a good person. You should just follow certain rules. You should be kind to your neighbor. You’re not really left with the gospel of salvation; you’re left with a moral code, and it really reduces it to sort of this moralistic religion.
Progressive Christianity downplays our fallenness:
The third mark is if you think you can be a good person, you must have a very low view of sin, which is another thing that progressive Christianity has. It’s this idea that people aren’t really that fallen and they’re not really that bad, there’s not really anything marring us, that we’re all good people at the core and therefore really do have an opportunity to be even better. You’ll find that in progressive Christian circles, there’s a downplaying of the word sin; there’s certainly no interest in talking about the wrath of God on sin. God is not portrayed as at all disturbed by or upset with sin. These are sort of the classic hallmarks of progressive Christianity.
Is this Christianity?
If you don’t have a divine Jesus and if you reduce it all to moralism and there’s no real fall or sin then the cross isn’t really anything that saves you. When you look at the cross, it’s just a good example of a good person. It’s not really good news. That’s what’s really sad about progressive Christianity. At the end of the day, it’s really not good news at all. It’s really that it’s all up to you. If it’s all up to us, that’s bad news. But of course, the real gospel is good news that it’s all done and completed in the great and finished work of Christ.
Here is the official link that explains the Eight Points of Progressive Christianity: https://progressivechristianity.org/