The dispute between the western world (mostly USA) with China over copyright isn't just for show. I imagine any random guy who made some game that involves some kind of demon could've slapped the Diablo title on it. When Jin Yong's novels were popular pretty much every computer game out there was Jin Yong's soandso game even though they clearly have nothing to do with the author.
At least these guys used the correct original subtitle, "Dark God of Destruction", for Diablo. You can tell someone is new to the piracy thing if the subtitle remotely resembled what the original said. I'm surprised Final Fantasy is now actually known as Final Fantasy as opposed to Space Warriors in China/Taiwan.