If Saru goes down, like the previous permanent Captain did, then strategically the most important ship in the fleet - the only one that can travel vast distances in the way it can - is under the command of an ensign with no senior leadership experience, no command experience, no tactical experience, and no knowledge or expertise of how to run a ship, a crew, or really anything beyond her own terminal. This puts the mission, the crew, the ship, the spore drive technology, Starfleet, and the Federation at risk. It’s one of the most astoundingly ignorant displays of leadership I’ve seen. On the other hand, you have Wesley who isn’t vital to the ship let alone Starfleet or the mission. I’m not debating the point that Wesley was handled poorly, I certainly won’t defend it, I’m debating that it’s both irrelevant to the case of Saru (as it’s a tu quoque fallacy) and that it is less egregious as a leadership action.
If you genuinely don’t see how, then I guess we just have a good ol’ fashioned disagreement.