In my day they did used to say that they sent us (125cc racers) out to see how many were killed as a way of deciding whether to start the Senior...
IMHO it takes more skill and judgement to race in the wet - or wind or whatever. Anyone can scrabble around and dig their way out of misjudgements in perfect dry conditions, whereas in the wet you have to simply get it right!
There obviously must be extraordinary conditions that make racing impossible, but they would have to have been really extreme to have made me chicken out. In '71 there was torrential rain, mist over the mountain and buffeting winds, but those who finished must have felt the same sense of achievement as I did.
The Isle of Man should be known for fairies in the glens, not on the bikes, and don't get me started on Elf and Safety!