There’s nothing wrong with him trying to sell a machine setup he configured and has tested and used.
There’s also nothing wrong with anyone NOT buying it because cheaper, better, faster hardware exists now already. That’s the joy of an open market.
Someone could also buy this and refit it with modern hardware and upgrade it - that’s an option and at this price, not a bad one at all. It works fine now, but could also work even better with a little tender-loving-care.
That’s not why these forums have died down - they’ve died down because the old CGTalk disappeared and got erased. The internet has always had caustic arguments and potent polemics - and if you’re afraid of that, head on over to no sites ever, since argumentation and debate make EVERYONE think better, harder, and change their minds or not. As long as there are no personal attacks (or other logical fallacies) it’s fine. It should be encouraged.
If you’re afraid of debate, log out and give up. Find a job in retail or construction. The internet is not going to be a good experience for you, period.