The word should is very negative. Its conditional nature breeds guilt and shame. Used about another person, it implies blame. Things we should have done are in the past and can’t be changed. Things we should do in the future serve to set up guilt if we don’t get them done. Acting how we should limits authenticity. If we replaced the word should with the word could, not only could we bypass the guilt and other negative feelings, we would open up limitless possibilities.
Don’t be so intent on finding fault or placing blame. Energy would be much better spent finding a solution.