I could agree with your advice, but martyns is not obligated to prove it publicly even if we ask him to.
Yes, doing so would just make the trouble bigger for him. We can argue about signing an old address, which might not work in certain cases (I'm not going into detail here to avoid giving him an excuse
) and signing an address can also be technically challenging for him but after making 400 post in indonesian laguage, it should be quite easy for him to make only 1 indonesian post again to debunk our research. If he refuses to leave a reply here, he wouldn't do himself a favor to get rid of the accusation, which doesn't seem to be in his favor at all, reviewing the evidence presented here.
If martyns is not a hacked or sold account, debunking our research here will be an extremely easy job for martyns.