Conscious attempts to block a bias like the Hindsight bias don't work.

You don't try to correct for a single bias. What I am saying is that if you find yourself in a situation where making correct decision is important and you know that this is the type of situation where your intuitive thinking is particularly likely to be affected by cognitive biases, you should try to make decision using your System 2. Instead of trying to block a single bias that affects System 1, we try to switch to using System 2 (of course, we have to pay a price). For example, suppose you are in a situation where you have to figure out whether a person X was negligent by failing to prepare for a disaster even if they did receive some information that something bad was coming. You notice that this is the kind of case where your ability to make a correct decision is likely to suffer from the hindsight bias. Hence you try to eschew your intuitive reasoning, opting to use deliberate reasoning instead. For similar reasons, while they do not avoid biases altogether, trials by court are strongly preferable to trials by a mob or trials by media as the latter usually do not even attempt to curb their biases, whereas the structure of the former encourages using the type of thinking that employs System 2.

Of course, switching to using System 2 doesn't guarantee that one's decision will be correct. And in some cases, switching from System 1 to System 2 might not be possible.