My five cents...
As long as there are humans acting as pilots, you'll have human error. These particular pilots made a mistake that ended in a huge loss of life. Unless they were shown to have blatantly disregard rules and/or shown reckless disregard for safety, why should they be sacked?
This should not be taken as diminishing the loss of life, which is terrible - but should loss of life alter the "wrongness" of the action? If we sacked/jailed every pilot that made a mistake, nobody would fly.