Upvoted for content. Though it strikes me as slightly redundant (gut feeling), I think that it covers some important points. Organizationally, I would change your thesis so that it better reflected what the rest of the post was going to be about -- the post struck me as rambling a little too much.

Thoughts:

Since I cannot prove my value system on an absolute scale, I sometimes restrict use of the word 'should' to technical applications where there's no ambiguity about the objective. For moral arguments, I like to use 'I think that you would want to' as a replacement for 'You should' -- it seems more intellectually honest, less opaque, and less provocative.

I interpret 'should have known better' as a data-sparse, unnecessarily antagonistic comment -- it doesn't tell the listener much about how they should revise their updating system and risks causing negative emotions toward the speaker. I also think that it causes future action to be more pain motivated because 'avoiding harsh correction' may become one of the listener's motivations for improving.