They didn't abandon "code is law." They legislated code to deal with a specific problem that they had a state interest to solve. Blockchains do introduce code

They didn't abandon "code is law." They legislated code to deal with a specific problem that they had a state interest to solve. Blockchains do introduce code as law, but if the code can change then they also introduce legislatures (the miners). Those legislatures have voting power equivalent to their % of mining control. The point isn't to make transactions irreversible; the point is to create a system of distributed control in which a decision to revert a transaction requires consensus among the miner/legislators.