[Chaebixi]

I think the way they justify it is that the waiver is "voluntary," e.g. you have to agree to it in a contract.

I personally wouldn't have a problem with that if the contract terms were negotiated by two sophisticated parties. However, the reality is that these contracts are often pro-forma and and "signed" without negotiation in the context of great disparities in power and sophistication. IMHO, the latter is troubling and shouldn't be allowed. There should be a whitelist of a limited number of types of terms that can be included in a pro-forma contract like these, and binding arbitration shouldn't be one of them.