I actually agreed with you until I read the order. It's about public good. Parler is arguing that Amazon is part of a cartel and that that's harmful to public

I actually agreed with you until I read the order. It's about public good. Parler is arguing that Amazon is part of a cartel and that that's harmful to public, so the injunction restores fairness to the market. The judge finds that meritless because they have no evidence that the cartel exists, and so the injunction does nothing for the public good. I'm certain the factual errors about AWS hosting Twitter's feed didn't help. Amazon argues that Parler had a role in the insurrection, so banning them is in the public good. Given the amount of content from the insurrection on Parler, it seems more likely than not that at least one person there was influenced by Parler. There is no requirement that absolute proof be shown, the judge is weighing probabilities here. It also helps Amazon that injunctive reliefs are considered an extraordinary measure, so Amazon wins by default unless Parler can reach a significant bar. This was a moonshot, and Parler knew it. They're asking for a strong legal response based on a pretty flimsy case. Even if what they are saying is true (which I strongly doubt, but what if), they simply don't have the evidence they need to get this relief.