You can critique the way we acquire information and use that to cast doubt on conclusions. But you definitely can not use those criticisms to add validity to any conclusions either. So I don't see how this world view does anybody any good.
At some point, you see nazis, you say "those are bad", and you just know you're right about it. In that sense, morals are a true compass when faced with endless doubt that can creep in if you want to be maximally scientific about things.