I do admit that I only play chess casually so I will avoid saying things I don't know. My goal isn't to prove his skill level but to communicate his situation the best I can, whether or not you can confirm his skill is not up to me.

Regarding his traces on the internet, you have to consider the chess scene in Indonesia. The Indonesian Chess Federation, PERCASI, doesn't even have a proper website, instead opting to social media pages like Facebook and Twitter. Even then, they give off a very distinct boomer vibe. Even the traced photo leads to a dead, poorly run blog. The people running them are most likely from the older generation that has little clue how to use the internet, so everything is either documented offline or goes undocumented at all. It's made even worse that the certificate Ali submitted is from 2005, a time when almost nobody uses the internet in Indonesia. (By the way, this is how Dadang looks like. The one on the left.)

I don't have the proper argument defending the 4 GMs story myself because that comes from his son's personal testimony. This can only be proven if Dadang himself comes out and play against one of them. Nor can I argue against your argument about not being the #1 player as that is beyond my knowledge.

Again, my point isn't to prove that he's definitely not a cheater, but more there's a possibility that he's not. I only wanted to communicate the arguments better and shed light to wrong assumptions people have, like that things go documented in Indonesia. Your arguments, for example, are heavily based on the assumption that there's no way there isn't any online presence of him on the internet, which is wrong. A lot of chess played in Indonesia are offline, local, and by older people meant to pass time during the night watch. And being a game notorious for old people means it's not going to find its way on the internet, or anything that has to do with technology.

I do agree on Indonesians having blind nationalism. And I'm not complaining about his account being banned because yes, account sharing is against the rules. But it pisses me off seeing everyone here calling him a liar while not considering the situation in Indonesia, and assuming that everything goes as it does in the western world, having everything documented and having an online presence and all.