He is very clear that he has no clue whatsoever what causes us to be happy, while at the same time slandering people's tendency to assume things, regarding MBTI type, which he clearly does not support. And thus he vaguely tries to connect happiness and MBTI types to each other in the hopes of breaking our assumption of the latter. Without any concrete arguements or thoughts to go with it, which causes him to remain innocent and excluded.
In other words, a lazy attempt to prove his point.
That's how I read it.