[greenyoda]

"Someone told their manager that they were uncomfortable working with her... Seems to me the co-worker did the right thing by going to their manager instead of being a jerk/passive aggressive."

You're drawing a false dichotomy. The third option (other than going to his manager or being a jerk) would have been to realize that not everyone at work is going to be his friend, and not complain about feeling uncomfortable because this woman wasn't acting towards him in the way he assumed she should.

A mature person would only complain to his manager about someone's behavior if it was clearly in violation of societal norms (hostile, racist, sexist, etc.). Feeling vaguely uncomfortable about somebody doesn't fall into that category.

[exstudent2]

We don't know how she was acting. If it was anything like her blog post, then he absolutely did the right thing by going to his manager. We only have one piece of information and it doesn't make her look good.