Funny how Shuichi’s idea of ‘for a sense of humour’ extends even to the floor with the [appearance of a chapel], and not just ‘childish looking things’. Never mind that there’s [a door with two of the seven deadly sins] written on it…

Besides that, in addition to his [judgement of Ouma’s lab], this reasoning is also a classic either-or fallacy. And because Shuichi leaves it at that, it betrays a lack of interest into why it’s really like this.