[watters]

While some reasons may be more compelling than others, there are no wrong reasons for quitting a particular job.

A manager saying you lack courage is despicable and reinforces the idea that it was an unhealthy situation.

What is or is not courageous for you is for only you and anyone you invite to advise you on life choices. It's quite likely (but for you to decide) that your decision to quit was, in fact, the more courageous choice.