Your point concerning the immaturity and false piety of those posting inappropriately in emergency forums is well made. This lack of humility and self-awareness reflects badly on Christians.
However, your reasoning around the non-existence of God, and the logical flaw of a good God allowing suffering does not really hold water. You of all people should know the logical difficulty of asserting the non-existence of God (this observation does not constitute proof of His existence). On the evidence before us, belief in a Creator is as reasonable or more reasonable than the alternative.
As to the existence of evil being glibly ascribed to "the devil", it would be more accurate to say that it flows from the free will with which we were created (suffering as a consequence of "natural" disasters is a more subtle debate). Although evil is, well, evil, the gift of choice and free will is incomparable. God chose not to spare us from suffering, but He was willing to share in that suffering.