Zavala was concerned with the wellbeing with the people under him. He removed his emotions from the situation so he could make a level decision, like a good leader should. Throwing every Guardian at a single threat because his friend went rouge and got himself killed, possibly getting more Guardians killed and starting a war in foren territory would, by definition, make Zavala a deplorable and self interested leader. He didn't reprimand the Guardian for going after Uldren, he didn't punish them for going out on their own without his authorization. He was rather lenient on them, letting them off with a brief talking to and and letting them know he'd have done the same thing if he wasn't in his position. As for Insurrection Prime, we have no idea if the Vanguard even knew about them. They were operating in an abandoned block of the City, and Ada sent Guardians on the Raid. The only reason she knew was probably due to them breaching the Black Armory vault. Do you really think Zavala, a Hero of Six Fronts, would let a Fallen operation exist within the walls of the City?

Perhaps, but Zavala’s ideologies and pacifist like strategies in recent memory have put us at odds with him. Including myself, the self proclaimed vanguard fanboy. As long as Zavala pretends to bury his head in the sand, it’s gonna spiral out of control.

I wouldn't call it pasafism more as caution. Zavala has long since written off the Reef as a bunch of crazy recluses who are too devoted to their Queen to interact with (which I agree with) so when he got news that Uldren had killed Cayde and was running around with a Fallen faction in the Reef, two thoughts probably went through his head; 1. That Cayde shouldn't have gone off to help the Reef the way he did & 2. That some major political movements were taking place in the Reef, probably involving Uldren trying to claim his Sister's empty Throne. I imagine this is why Zavala didn't jump to action, because it wouldn't be worth the efforts directing the entire Guardian population to settle a personal debt. So he says if another Sov wants control over some barren string of asteroids, let them. The damage is already done. While I might not agree with that decision, I definetly respect it considering the position Zavala is in. And he isn't burying his head in the sand, he authorized Guardian involvement in the Dreaming City after hearing about their Taken problem. He hasn't frozen all Vanguard Activity, he's just grown more cautious in his strategy.