I think it's clear that this was not at all an "arm's length negotiation" with an independent Special Committee but, at the same time, it's not clear that any harm was done to Tesla shareholders.
Tesla traded up on the news that the pay package was re-approved by shareholders and the similar voting outcome (72% vs 73% originally) in light of all of this information seems to indicate that the shareholders genuinely want this to go through.
Tesla traded up because there was a risk that Elon would have a hissy fit if the vote failed, and he would single-handedly destroy the company. The fact that the risk of Elon rage-quitting was priced in demonstrates why the vote wasn't an appropriate solution in the first place, the minority shareholders are coerced to "take it or leave it" in a way that corporate law is meant to avoid.
Tesla traded up on the news that the pay package was re-approved by shareholders and the similar voting outcome (72% vs 73% originally) in light of all of this information seems to indicate that the shareholders genuinely want this to go through.