I remember when the ABE was still around. I encouraged an American Baptist Church to withdraw and talked to the President of ABE. It was then I relayed the similarities between the American Baptists and the Downgrade, where Spurgeon saw the Baptist Union was even further down the path than he once thought. The ABE President disagreed until about 3 years later when they disbanded, he said basically what I said 3 years prior. What changed? I believe very little changed except his perception.
The UCC is even further down the path of the Downgrade. As a result, their liberalism will only have a negative impact on the local churches, including conservative churches. I would call the Pastors to be more concerned with their flock than the denomination, as God does not care about the denomination but he loves his church. Sometimes the best way to care for your flock is to remove yourself to a denomination.