alt Hacker NewsWorkers are so much more militant and punitive than executives. It's not other executives that will try and hurt his career because he made a decision and went with it. It will be the worker bees that will attempt to hurt him 5 years down the road -- without even knowing the full story.
There are very practical reasons to not hire someone who abruptly dips after less than a year on the job that have nothing to do with being punitive.