Islam forbids lying, not taqiyya. See how that works? The OT God and Allah both have separate rules for how you deal with people inside the community, and how you deal with outsiders. I assure you, modern day Islam is closer to Deuteronomy than anything you're living. Now, if you're saying that the OT is wrong about what God is "really" like, I won't argue. I've found that everyone who believes in God is also such an expert as to His innermost self that they are practically soulmates. It's almost as if every believer has his very own God, and it's astonishingly compatible with their own precious self.
The one true God does not lie and does not require lying. He is a just God who allows freedom of choice, whether the choice is good or bad. God does not violate freedom of conscience, the god of Islam does. They are not the same.
Believers are sinners—through belief they recognize this.
They understand that the only way to God—who is not simply pure but purity itself—is to first recognize not that they are “precious” but that they are sinners. Broken, flawed, sinful, hopeless. But God has provided the solution—redemption through repentance and faith.