Ruben, I think you missed the point.

UBBCentral.com Store - https://www.ubbcentral.com/store/
The way it is presented, everything within that URL appears to be sold by or with some connection to UBBCentral.com.

Why does UBBCentral.com, "Building Communities Since 1997," attempt to trick people in to thinking they are selling computer hardware?

The name listed within the header is "UBB Store," just below, "UBB Central." No explanation. No disclaimers.

When hardware is purchased through UBBCentral.com, because UBBCentral.com is also directly selling other products (UBBThreads software) alongside these, wouldn't UBBCentral be partially liable if a bad sale occurred on these, too?

The same page has the UBBCentral brand name and logo in the header. It also has "Purchase" in that same header. This could very well lead one to believe that whatever is listed under the "UBBCentral" / "UBB Store" name, is being supported by them as well.

To further, "Sales Questions" is noted, but it's not clear what "Sales" is referring to.
https://www.ubbcentral.com/tickets/index.php?type=sales

Can Interested buyers ask questions about the "1983 MAC Paint User Manual" which is listed for sale in the UBB Store?
Interested buyers could also call the "UBB Store" @ 954-871-2693 (Listed in the top-right of the UBB Store header)

UBBCentral sells "1983 MAC Paint User Manuals" -
https://www.ubbcentral.com/store/item/Apple-Macintosh-Vintage-MACPAINT-1983-User-Manual_331341604599.html

how is this even remotely helpful to the UBBCentral motto, "Building Communities Since 1997?"