To my understanding a pledge such as the one by Blockstream is legally binding.
Correct. And in addition to the pledge we have the DPL and MIPA which are two additional distinctive ways that users get protective coverage. These provide additional assurance in case of any limitation or issue with the pledge (and vice versa). (MIPA is kind of narrow: it says the inventors are also able to grant licenses for defensive use)
. Will u support it if they make a similar