Instead the crux then seems to be "fundamental political rights". I guess I don't see it that way. When you go into court to sue the government, or even in tort against a private party, sure. But in a contractual relationship the right and reason to go to court flows directly from the contract. The fundamental right here is the parties' ability to form an enforceable agreement under terms they agree to. (I should note as a matter of rhetorical fairness that the New Deal Court discarded the notion of "liberty of contract", but as a political philosophy matter I still think it is crystallizes an important notion of freedom.)
I didn't specific it earlier, but I think restrictions on binding arbitration would also extend to contractural prohibitions on class action lawsuits, since the two typically go hand in hand.
It doesn't eliminate the power disparity, but eliminates new mechanisms that are used to increase it as well as protecting the mechanisms that have traditionally been used to protect against it.
> The fundamental right here is the parties' ability to form an enforceable agreement under terms they agree to.
I disagree, there are other rights that are at least as important that must be balanced against that.
Also "terms they agree to" is a slippery concept, and it's arguable it doesn't apply to 99% of the contracts "agreed to" today (think click-throughs and other walls of tiny text, which are typically neither actively negotiated, read, nor fully understood by one party as an essential matter of practicality).
I think the root of the perceived unfairness is that forced arbitration concerns using a power disparity to force renunciation by default of fundamental political rights (access to the court system) to the benefit of the powerful party.
The take it or leave it attitude is fine, but only when the parties are on fairly equal footing.