Gotta disagree with you there. First off, it doesn't add them to your spells known, it just lets you cast them as if they were among your spells known. (It's a subtle difference, but it means you can't do stuff like swap them out for different spells when you level up or use them to power a dragonblood sorcerer substitution level.) Second, it clearly constitutes an exception to the general rule that spontaneous casters can't cast sanctified spells, and exceptions have the highest priority when rules conflict with each other.