Personally, I think it is the worse thing you could do if you were purchasing from a "real estate" perspective. I agree with you 100% on the above issues.
There's also all sorts of other stuff happening at the domain parking level. Some of it not even known to those parking the domains.
To the original poster, there really isn't a whole lot you can do in this instance. If it is a generic term or phrase, the chances of litigation are slim to none. Although you might be able to find a lawyer in the States to accept the case for a mere $50k USD up front with no guarantees. Hmmm, that's about $46k more than what the initial offer is. ;)
Actually many of those fools are laughing to the bank. Domain names have made people millionaires. It's a business model just like anything else online.
If you really have to have it, negotiation is now in order. ;)