Nobody wants to be taken advantage of, either by fakery or pricing. Many want to respect the history of the weapons and integrity of the hobby. Of course there are some who are strictly in it for the money. Even collectors want a return on their investment. I've know forum guys who charge what is the max the market will bear. Even on items they found at substantially less.
That being said, these buyers and re-sellers are only doing something morally illegal. Distasteful to many or most of us, but not against the law. Using the forum to report and inform others is being helpful. But scheming against another I don't think is helpful. The marketplace has and always will be buyer beware. Books, past experiences, asking questions on a forum, pictures, friends. Being well educated in one's hobby is a better way to deal with these unscrupulous sellers.
We should strive to be fair and friendly.