Again, not true.
Protestants - as in Main Line Protestants (Baptists, Lutherans, Episcopalians, Methodists, etc) all have governing bodies of some sort who determine the theologies of those particular churches.
"Non-denominational" churches are those who reject even those Protestant churches' theologies. Those are the dangerous ones, many can't even be considered Christian, as they do things like disbelieve the divinity of Jesus, of the Trinity, etc.
In the current era, there are many who, when confronted with their own behaviors being out of sync with the Church, decide that instead of changing their behavior, they simply change their Church. It's more convenient that way.