If you actually believe that violence might be the right thing to do, then you assign non-negligible probability to

• the discussion will convince you that violence is indeed the right thing to do
• you now have moral imperative to do violence, and you will act on this or convince others to act on it
• you will want the discussion to never have occurred in the first place, because authorities can use it to track you down , and suppress your justified violence

If you want to discuss a coup or something do it in a less easily traceable fashion (not on a public forum. Use encryption. ).