The order of your specs doesn’t actually matter for this particular case. You are using an all-defense strategy, and Bulwark of Righteous Fury is an offensive legendary. You would need to move the toughness slider closer to DPS for it to pick that legendary. For all toughness, it’s choosing a combination of gear that has better overall stats for pure toughness, mainly a higher ilvl item in the larger chest slot (more total armor/stamina), and more total mastery.