Gaffers that would on his asshole like it was a jolly rancher were so gullible and naive. If you've followed this industry for a while, its very easy to make educated guesses and be somewhere close to right most of the time. People treated his guesses as gospel.
Eventually he ran out of things to guess about, so he started saying outlandish shit hoping people would suck it up. A lot of people did, but it was very easy to see what he was doing. Him playing a guessing game with someone's personal life was the final straw, because the person he was guessing about was having none of that shit and was dealing with very dire personal shit.
Mortimer was a fuck up of the highest degree and a huge asshole to boot.