People mean different things with "trustless". Its trustless in the sense that you yourself can apply the rules and verify that each block follows the public r

People mean different things with "trustless". Its trustless in the sense that you yourself can apply the rules and verify that each block follows the public rules. The "agreeing" is only within the rules and the rules are in the code. So you have to trust (or verify) that the code actually does implement the rules the way you want them to be.