1. Is it justifiable to walk into a shop?

2. John Does walked into a shop and murdered all present. Was he justified in walking into the shop?

Answering yes to 1 and no to 2 is a contradiction in the same way. But, is it really valid to separate the action of walking into the shop with the murder of those present? Is it really valid to separate Sutcliffe's belief from his actions?

Condoning rape and murder only comes into play if you also answer that God is the source of all morality. In that case, doing God's will is by definition moral, and if he wants you to rape and murder, well, you bite the bullet.

1. Is it justifiable to speak freely?

2. John Doe announced that a crowded theatre was afire, and people died in a resulting stampede. Was he justified in speaking?

Nobody ever addresses the separability issue you describe.

Basically, a belief is justified if there are good reasons for believing it. What are "good" reasons? It depends on your philosophy. But presumably the reasons are separate from the belief its self. If you cite certain reasons for believing one thing, but then refuse to believe something else on the same basis, you're being inconsistent.