The right to contract is not unlimited, especially with regards to self-contradiction. Hence not being able to sell yourself into slavery. Even these arbitration clauses recognize they'd be blatantly unenforceable if they didn't carve out exceptions for eg determining their own validity in a real court.
Re #1 - a clause that allows one to completely opt out of it, but only within 30 days after opening an account, by snail mailing (an onerous communication method compared to the customary method of the relationship) to a specific address buried in pages of terms. That's basically purpose-designed to take advantage of consumer uninformedness/laziness!
Re #2 - there's a big difference between how much effort will be spent when opening an account, versus looking into a problem.
Your general argument is casually resting on these common falsehoods that consumers proactively read tens of pages of terms, that interpreting dense legalese (including the context of relevant case law) is straightforward to the average consumer, and that companies aren't just continually attacking consumers with garbage terms [0] just because they can (most likely their legal staff justifying their own paycheck).
That's not surprising - it is after all how the status quo is perpetuated, and how attorneys gatekeep access to the legal system (thus undermining equal protection). It's just not right, in the sense of morality or even correctness.
[0] http://www.law.harvard.edu/programs/olin_center/fellows_pape...