My first year lecturer told us this in the first class, na sijawahi sahau, "Everyone is entitled to an opinion, but if your opinion is not based on facts, then it is wrong." Even in gossip, wamama hukosoana to make sure the mushene is accurate. All I can say, mtu akikuletea opinion yake...mwambie atoe facts/evidence...that's a start to having a constructive debate.