If John is like me (an older guy), we spend our days dealing with everyday business issues, and he probably has others deal with the nuts and bolts of his online and sales business. He probably goes on the internet when he gets a spare moment, or perhaps on his time away from the 'office', only to find 3 pages of whining, slandering, John haters, and other associated keyboard diarrhea splashed onto his forum.
Because you may think it is a good idea for John, or one of his employees to be sitting on a computer all day waiting for someone to post a ##### on a forum he doesn't own, it is not a very efficient use of resources, and it just doesn't fit into the business model.
Frankly, I would probably have a much sharper tongue than John regarding the way some people expect for him to deal with things in a public forum without any real way to determine who he is dealing with.
Unfortunately, we are now in the era of instant gratification, where those who cannot co-ordinate Mr. Brains and Mr. Mouth now have an additional avenue to show the world that they should exercise restraint before they type their thoughts on a keyboard.
Personally, I would rather not conduct business in an open forum. There are too many short fuses out there that will misconstrue anything at the drop of a hat.
And to all of the keyboard warriors out there...your tone would definitely change if you were to deal with things face to face...mano o mano, with the Marquis of Queensbury rules.
Or even better...pistols at dawn.