I've noticed that myself over the years. It seems like every person who is involved in the mental health field usually needs to have some kind of help themselves. My wife included. She often comments when she sits through seminars that many of the other attendees seem to treat the time as a personal therapy session versus actually getting something from it that they can apply to their jobs.
What your wife experiences is common. I have brought it up with the psychologist I have been seeing on and off and she says the same - a lot of her colleagues are a mess. This doesn't mean they can't help others, but there are risks.
I think part of it goes back to the fact that they have everyone's problems dumped on them and if they don't have some kind of release themselves, things can get off the rails.