I can understand Dameron being in trouble for disobeying orders when he went after the last cannon on the dreadnought. However, he was not the person in charge of the Resistance's assets. That responsibility fell upon Leia and Ackbar and Holdo and whomever else was higher in rank than him. If the bombers were that valuable, and the mission was too risky for them, then they had the ability to abort the mission and recall the bombers. However, it looks like the higher ups acceded their authority to a subordinate and then blamed him for their f**k up.