Just look at any thread on this forum: people contribute information and correct each other and it's interesting, not patronizing.
Geeks find the constant back-and-forth of corrections in dialogue to be interesting and educational. Non-geeks do not; they lose interest by about the second iteration, and will become annoyed shortly after.
Little Edit: if you think describing 'I don't agree with you' as an 'altruistic desire to educate' and single-handedly preserving the 'validity of discourse' and the 'truth and correctness of human understanding of the world' is anything short of absurdly presumptuous, you might want to re-read the linked article very carefully.
Not necessarily. Preserving accuracy in a complex system with a lot of data flowing all over the place requires multiple checks throughout the system.