Ah! Got it now; only some are required to give evidence, but not those who demand it!
Actually, I did ask what I thought were some pertinent questions and I would have liked some answers - or at least thoughts from those who seem to know - and has anyone yet answered the OP in a satisfactory manner?
The OP would seem to me to be a perfectly reasonable assumption, judging by comments I have heard from people I know (and in my family) who are staunch Labour supporters but would agree with the original poster.
JBC seems to embody all many people may think is stereotypical of a Left-wing politician - possibly that could be a hindrance if you have a wish for them to win the next GE bearing in mind that the majority of voters are not to the extreme left, more to the left of centre. Long-haired (now cut!), bearded, scruffy, anti-establishment, bike-riding Islington politician. Will that appeal to the ordinary, decent, hard-working Labour voter? Will they identify with him?
Certainly a lot of women seem to do so or are swayed by some sort of charisma if Mumsnet is anything to go by.