What coincidental timing! I was just listining to Johann Hari's "Everything we know about addiction is wrong" TED talk[0].
His central premise is that the drug policies of the last 100 years have marginalized and disconnected addict populations. His proposal is that connection is the opposite of addiction.
Interesting to hear temporally adjacent to the idea you express -- providing the means for marginalized populations to rejoin society should be priority #1.
I agree with you in theory, but it's also important to understand the SO perspective on this issue. It seems like they believe allowing the community to "drift" by not modding things defined originally as off-topic will be harmful to the community in the long haul.
How many times has HN discussed the digg/reddit/HN decline in quality as the population grows?
In their minds (and I have to give them the benefit of the doubt given their awesome accomplishment!), keeping strictly on topic is one way to prevent the point of the site from drifting.
It may be that the SO people "want" is a better one. But that's the decision that Atwood & co. have made. To wish for a SO that allowed off topic responses is to ask for a different product.