They all must realize that they don't have a direct connection to God and do not receive revelation. They justify their lies because they rationalize that even if the Mormon church is false it's a good way to live and helps to keep people out of trouble. Therefor the ends justify the means. Lying is okay if there is a good outcome.
They have all had the Second Anointing or "Second Endowment," which guarantees them the "celestial kingdom." They are told that God is bound, and can do nothing about it. They can't "take innocent blood," but have a hundred different points on exactly what constitutes "innocent blood"; there is a ton of wiggle room on that. Recipients cannot "deny the 'Holy Ghost,'" but the church has never defined exactly what that means. But all else, dishonesty in business dealings, bearing false witness, even adultery, takes no toll on one's ability to get to the CK. I think it's after the SA that we see the worst behaviors emerge.