They wanted to leave that up to the states if they wished.
Your statement in this post is at odds with your statements in others, including your petty “baby Jesus” post. You’ve been saying the lack of a direct mention in the Constitution means we’re not a Christian nation, but now you’re talking about the lack of a state church meaning we aren’t a Christian nation.
There is a vast difference between saying “We are a Christian nation, but we will not have a state church or religious tests” and saying “We will have a state church which you must join or risk being persecuted.” The fact that they didn’t say the second doesn’t mean they didn’t say the first.