We all have to work within the rules to maintain our certificates. Your questions are no different than a passengers questions of your competency.
In this case from what you wrote it seems that a qualified mechanic did perform an assessment and presumably worked within the guidelines in the maintenance manual.
Under this circumstance your concern should be generalized and kicked upstairs for procedural review.
Of course you also have the right and the responsibility to to form judgements based on your manuals, but be careful that these judgements are not perceived as punitive in nature.