Earlier quoted context omitted.
You didn't argue for why the chain analogy applies here. You just argued that we should reject the entire agreement if one part is so egregiously bad that it outweighs the others, which is obviously true. Why does the "weakest link" analogy apply to the actual TPP, which, as far I know, does not call for the murder of any children at all.
The agreement is supposed to be a chain. The things in it are supposed to be related in some way, otherwise why are they together? Dumping many completely unrelated things into the same agreement so that things that should not pass have to be passed in order to do things people want is the thing so egregiously bad that it outweighs everything else. It's a chain with a link so weak it doesn't even exist. Otherwise you…
A better measure for a deal like this is the geometric mean of its components. If one component is zero, the entire deal is worth zero, but otherwise each component contributes to the aggregate value of the deal.