I wasn't surprised when I found out it was a law firm either. I've had the good fortune to work with some of the good ones, but legal marketing in general requires a very sensitive a-hole detector.
Bad clients are bad clients, but speaking from experience, it can be taken to an entirely new level when the bad client in question happens to be a law firm. Some of the less savory high volume practices can be especially bad, and they all go out of their way to project an air of competence and professionalism that disappears pretty damned quickly. Personally, I think part of the problem with those guys is a serious sense of arrogance and entitlement, as if their being a law firm will force you to go away despite not being paid. And if you don't, well, they can always play games to delay and string you along. After all, you're paying for representation directly. They can at least swallow the opportunity cost of dealing with you somewhat easier.
Nowadays, if I'm contacted by a law firm for work, I look into their reputation very carefully. In my experience, corporate law firms--regardless of size--aren't a big deal compared to some of the high volume personal injury/immigration/divorce/etc. firms. And yes, I realize I'm doing a lot of generalizing here.
If it's a law firm, then to me it is surprising that they would actively interfere with this guy's other professional relationships. If this really is as it appears to be, the potential damages both from interference with existing relationships and from defamation surely put this in "worth talking to a lawyer" territory in most places.
In my country, if they'd interfered with existing business relationships causing expected revenues to be lost, they'd made potentially libellous statements that caused a major source of expected future revenues to permanently block access, there was ample written evidence that they did these things deliberately and that actual losses were and would continue to result, and there was ample evidence that the victim had previously been well-regarded and able to command a certain rate for their services, I wouldn't want to be their position, law firm or not. Situations like this are exactly why defamation cases can result in such huge damages being awarded.
Well, maybe I'm just jaded by a recent experience with a former business partner who was an attorney himself. They guy had provably stolen over $100K from the company and our attorney basically charged us $20K to let him go. It was a valuable lesson to me to never go into business with an attorney again.
Not all attorneys are crooks. My daughter is attorney for business (Droit commercial, France) and she is definitely not a crook. In fact they spend a significant amount of work time trying to get the due money from clients. Please don't generalize.
The real problem is that there is no efficient system to weed out the crooks. There are no efficient pressure against them. Psychopats are king.
I know they are not all crooks. The problem is that you assume that somebody is not when you enter a partnership with them. If that partnership has to go to court you are at a significant disadvantage if your partner can represent himself against you, aside from the fact that he probably knows the law better than you do.
While I knew a few who successfully worked full time at large legal firms, I once worked full time for a smaller firm (about 60 staff). Never again. I left after 6 months and vowed to never work for a law firm again. Life is too short and there is plenty of opportunity out there for talented people.
The ironic thing is that my experience was nearly 20 years ago. While so much has changed in the last 20 years (in Internet time, that's like 400 years, and I have more RAM in my phone than the Unix server supporting 40 users on serial terminals), some things haven't, especially where humans and the legal profession are concerned.
I don't intend to paint all attorneys with the same brush--I now have good relationships with several attorneys that I use for businesses; I still would seriously question any job working for a legal firm.
Nowadays, if I'm contacted by a law firm for work, I look into their reputation very carefully. In my experience, corporate law firms--regardless of size--aren't a big deal compared to some of the high volume personal injury/immigration/divorce/etc. firms. And yes, I realize I'm doing a lot of generalizing here.