The original comment asserted that there are “probably” a finite list of reasonable things everyone could agree on. The examples were parenthetical and surely not meant to be the last word.

The point they were making (rightly or wrongly) seems to be that contract law just isn’t the right way of managing consumer-business relationships. I suspect that actually meshes with the intuitions of a broad swath of the population, who want a reliable, predictable, consistent, and consumer-beneficial set of norms and laws around all consumption so that it is easy to manage and understand when you are departing from the norm and to be able to confidently conduct a public life knowing that your purchases are not subjecting you to any surprising gotchas other than having lost the money and having acquired a product.

You could take this line of thought charitably in another direction to assert that “unusual” agreements are presumed unenforceable but not that there are no legal mechanisms for adding additional clauses.