Well, since you ask:
Imagine that I have a business, and I've obtained a domain name for it. Let's call it my.cooltld. I'm in the early stages of building up the business and the brand.
Then someone announces on the Internet that "if you're interested in obtaining the domain my.cooltld, we can help you to negotiate with the seller". That gives the impression that the owner of the specific domain my.cooltld is open to selling it. And that in turn gives the impression that I'm not very committed to my new business venture, and that impression is not good for my brand and my business.
I'm with Brad here. I think that's out of order.
For some domainers, the only reason domains exist is to make money for people buying and selling them; they don't have any other purpose. This kind of domainer doesn't have any sense of responsibility to people who are impacted by his business dealings. That may be legal (or not, and that may simply depend on how good the lawyer is who is making the case). But to my mind, it's not professional or ethical.
I help businesses buy domains from other active businesses all the time. I think I have not done them wrong, or forced them to sell. They are capable, adult human beings that can make business decisions just fine.
They are capable enough I would say to also realize that if a person contacts you about buying something they do not own, it is not to be regarded as a purchase offer but something else.
It is unfortunate that such correspondence can be used against the domain owner party, that may have had nothing to do with it, "in a court of law". But maybe "the court of law" is the issue in that case.
I think the key here will have to come down to semantics.
Of course you can do outreach and sell your general brokerage services. Of course you can target that outreach as precise as you can. Of course you can even say that you can try to help acquire a specific name, worded right, in the right context.
What you shouldn't say if you value your credibility, and industry status, is "I am selling" or "I can get XXXXX.com for you" or "I know this seller" or "I have a lead" and so on. Anything that would let on that you represent the owner.
Because unless you really do, you are misrepresenting fact, and could potentially increase the risk to harm the owner - and shoot yourself in the foot in the process.
IMO.