I think Waters' 'thing' isn't quite that he distrusts emotive effectiveness but that he is singing from the perspective of someone unable to achieve it: his thing on all the big PF albums isn't "I spurn these effects" but "Because I am afflicted by the world's woes my vocals will be pained, stunted gestures towards effect." - the vocals on "Wish You Were Here", "Mother", "Money" are kind of knowingly broken attempts at rock/soul effect rather than attempts to spurn them. (And on "Great Gig In The Sky" that godawful Bodyform-style yowling from the guest vocalist is I guess meant to represent the ecstasies of whole-soul achieved technique, which as the title suggests is something celestial rather than earthly-achievable).

In other words this is Protestant Rock - so there IS actually an element of distrust in there but it's distrust of effect as a false claim rather than emotion as an end in itself.