I think this should be considered as spamming. You have no connection to this campaign, so you are not entitled to demand anything from the participants in this campaign. Threats of negative feedback are really pathetic from a guy who himself has a negative trust as low as -539...
You do not need a connection to leave negative feedback. I consider people who advertise DiceBitco.in untrustworthy because:
1) DiceBitco.in has scammed by not paying out winnings people should have received. This has been established earlier in this thread.
2) Participating in a signature campaign is promoting it.
3) Promoting a scam for money is untrustworthy.
If you dispute 1 or 2, I'd be happy to hear your arguments. 3 is my personal opinion (which I think most people will also agree with), and trust is opinion based.
By giving negative feedback you are putting the blame on the wrong people which have nothing to do with DiceBitco.in scamming. Methinks, the total majority of participants would be happy to get money right now and be done with it. What you are going to do is called blackmail, and I'm doubtful that you do it just for personal reasons.