Thin Man Films is a British film production company, based in London. It was founded in 1988 by director Mike Leigh and producer Simon Channing Williams to produce Mike Leigh's films. They chose the company name because both founders were the opposite of it.
Mike Leigh and Simon Channing Williams are not thin
The statement is not definitely correct nor definitely incorrect because it does not state their current weight. Based on the context they were definitely not thin when they created the company in 1988, but there is no way to know if they are still that weight, or if they have lost weight 31 years later. One or both could also be dead. I think it was difficult for the system because it did not have the logical thought process to think they may have lost weight since 1988. 
( z1 thin :polarity - :ARG1 ( z2 and :op ( z3 person :name ( z4 name :op "Mike" :op "Leigh" ) ) :op ( z5 person :name ( z6 name :op "Simon" :op "Channing" :op "Williams" ) ) ) )