How can you call it "The Truth" when much of the belief system is based on the opinions of 8 men (aka: Bible based principles are still not Biblical and are man made rules) or it can change or flip flop (aka "New light")?
Truth does not change. It is a constant. New understanding makes old understanding false in the present just as much as it was in the past. Calling it "The Truth" is the antonym of what it truly is - a belief and a belief is just a nice way of saying opinion.