You are just plain wrong. His lack of a valid licence might not have affected his ability to fly the aircraft but it certainly showed a complete disregard for the rules that are in force. This to my mind is a dangerous trait in a pilot. Rules are their to stop you doing stupid ****. Unless you are flying regularly and have need to bend the rules (military pilots for instance where life and limb are at stake for real) then doing anything bar flying correctly and you are a cock end of story.
Like most ppls I don't suppose he had much follow on training or oversight of his flying. All very sad for the other people who are now dead due to his behaviour and for everyone concerned's families.