Yeah, cynicism is actually terrible for science, and as a result many scientists aren't overly cynical. I think it's something that happens as folks mature: they tend to look for the positives in papers, rather than the negatives.

This has certainly been my experience in cryptography: as a student you often start off proposing schemes which get broken by your advisor/collaborators (not out of malice, but just because broken schemes are broken), and so you learn to react to novel ideas with "how is this broken?". However, as you mature, you realize that all new correct ideas arise from the ashes of many broken attempts, and so your reaction slowly changes to "how can I fix this?", leading to an overall more positive outlook on both your work as well as others' work.