My word "many" clearly refers to all three categories I mentioned: Unitarians, deistically-inclined and Freemason Christians.
Those categories do include "many" Founders, indeed, only a few fall into none of them -- Washington's friend, John Jay comes to mind.
George Washington himself is an excellent example, clearly a devout Christian and a leader in his church.
But he was also a leader amongst deistic-Freemasons, he often referred to the protections of "Providence", but never (so far as I know) to the deity of Christ.
It is also said that while Washington attended various church services -- including Catholic -- he refused to take communion.
Bottom line: while Washington was not Unitarian, he was a deistically influenced Freemason Christian.
Others like Benjamin Franklin, John Adams, Thomas Jefferson and James Madison were less traditional Christian and more influenced by Unitarian, deistic Freemason ideas.
Do you disagree?
I do disagree. You would need to show me most of those men lived secret lives. Their church affiliation (as I posted) and public quotes say different.