Fortunately I've not seen it very often at any ATSU I have worked at.
Before this thread goes much further, I have worked at several units over the years, the only, supposed, incident of bullying, was when a trainee did not receive the glowing reports they felt they deserved.
I am not for one minute saying this is the case ,as in the one reported , but come on; there are always two sides to the story.
ATC was never a profession for the meek.
If it can't be sorted, face to face, then you are in the wrong job.