It’s actually really messed up that they do this, imagine people in any other profession sharing clients personal and contact details online!! And also attacking clients because they have reviewed the services that they provide! Although, I guess from the very nature of the work they do, most do have some serious mental health issues, so maybe it is unrealistic to expect them to act with any decency.
Also, what they are doing is in breach of GDPR laws, so technically they could get in trouble with the law for this, but then I guess they know that punters are not really going to want to go to the authorities regarding this kind of activity.