Your post sounds too much like judge the message by the messenger.  One needs to do their job to the best of their abilities.  Also stakeholder analysis comes in to play.  As an employee you have a duty to see that things go as well as possible.  If people can't handle the feedback to improve then discussions need to start.  If it turns out that what you have to contribute is not appreciated then it is time to move on.  Nobody spends an entire career at an employeer and if you are not developing and or appreciated you have to go because nobody else is investing in you accept yourself.