I would suggest it's unlikely he was part of the problem, given that Uber type behavior would never be tolerated at Target. That may be because of ethics, or it may be because they were sued into ethics; either way, not tolerated.
Burning bridges can be a boost to your reputation. Imagine the number 2 person at Enron left after six months at the job and made the same statement - they would have been hailed as a leader of excellent judgement and moral standing after the collapse.
Burning bridges like this?
Could it be that he was part of the problem and attack is the best defense? Because I cannot find any other reason why somebody would do this.
It is also strange to say that because he was no. 2 in the company and if you are no. 2 you should be able to fix things you do not like.