Arbitration is done by a company picked by Amazon, paid by Amazon, hoping to remain in business with Amazon, deciding about a conflict between Amazon and a random customer. In whose direction are they likely to err?
Who exactly is that company? One of the first steps in arbitration is for both parties to agree on a choice of arbiter. Looking at Amazon's webpage it names the American Arbitration Association which appears to be a pretty big non-profit. Step two in their road map here includes the arbiter choice step:
https://www.adr.org/sites/default/files/document_repository/...
If amazon is just insisting on "their guy" then I would think that should be pointed out in much bigger letters. From Amazon's perspective I can see lots of incentives: faster, cheaper, no appeals, no class-actions, probably no giant punitive judgements. But they may not have any better chance of actually winning them.
I can't comment on the arbitration clauses that Amazon uses, but the arbitration clauses I've seen usually says the arbitrator is randomly assigned by the american arbitration association.
This is a late reply, but there are a couple big differences. The courts could create a class action, or join multiple claims. Avoiding a class action, where the individual claims are too expensive to be worth pursuing, but as a whole the wrongdoing is significant is one of the biggest driving forces in mandatory arbitration. But these don't apply to the linked case.
Discovery is more limited with arbitration, third party discovery is very limited, usually use witness statements instead of depositions. Arbitration almost never forms precedent, and arbitrators are not bound by case law/precedent. Decisions made by an arbitrator can only be appealed under more limited circumstances than if made by a judge. This means it is less likely a decision will be made based on the existing law. A court can grant interim relief, generally an arbitrator can not. A court will sanction parties that act in bad faith, in practice an arbitrator will not. A court judgement/sanction/relief can be enforceable in a way that an arbitrators finding would not be. This adds up to in practice making a successful claim more difficult for a wronged consumer
Arbitration is generally cheaper, limited discovery is cheaper. Not being limited to the same evidentiary rules and to respecting precedent allows the arbitrator to make more equitable decisions, that conflict with the law. Arbitration is faster.