For the benefit of the sceptical Mr Irish, my justification for why I do and will continue to expect cyclists to be nicer people.
It seems to me blatantly obvious that, for any activity people can choose to participate in, (a) the people who choose to participate in it will almost always be a slanted section of the population in one way or another, and (b) participation in it will have an effect in them.
To give an example: I would be amazed if people who choose to volunteer for the TA were not a slanted section (e.g. more militaristic) of the population; and I would be amazed if participation in the TA did not have some effect on their character (make them more militaristic, but also change their approach to leadership, discipline, etc). Another example could be rugby players, which I think
@MacB was citing, though I would not have done so, not being a rugby player and not wanting to promulgate my own stereotypes.
So I would be amazed if people who choose the open air rather than a confined space; who choose their own resources rather than relying on external power; who expose themselves to the vagaries of nature rather than insulate themselves from them; who match themselves to nature rather than using noisy, throbbing, vibrating engines to overcome nature; etc etc, did not tend to be different from the population as a whole, specifically, a nicer (under my definition of the word) sample. And I would be amazed if exposure to cycling did not tend to change people's character, again, in a direction that matches my definition of nicer.
So I will continue to expect cyclists to be nicer people, and when I meet or hear of one who is manifestly a knobhead, I will continue to be disappointed.
(
@User has, I think, already pointed out the fallacy of thinking that a population average - a "tendency" - has to apply to every member of that population to be true, although, as ever, he pointed it out more succinctly than me.)
(I think the recent explosion of interest in cycling in the Surrey Hills, the setting of the OP blog and my home turf, has been in a style of cycling where the factors I listed above may be less strong. I would expect to sample a different spectrum of attitudes in the cafe at the top of Box Hill from a Youth Hostel full of LeJog-ing cyclists. But I happen to think those factors still apply even if less strongly.)