I think that those are questions that people need to ask of themselves -- assuming they feel the need to do so. Secondarily, I suppose it's worth asking other people, if you do so in a spirit of sincere inquiry rather than as a method to create a soapbox to articulate your views. Unfortunately, this thread has primarily consisted of people asking/demanding/shouting the questions at others, or about others, and then shouting out their own answers. That's not the way to come to understanding.
If you genuinely want to know why other people do something, then ask them -- in an open-ended manner, such as, "Why do you do that?", not "Do you think that's going to make you enlightened or something?" with the strong implication that if you do think so, you're a dummy. Then listen to the answer. If you don't want to do that, soapbox away, but don't kid yourself about what you're doing.
I know this comment will take away from what Mary is saying and to be honest I think what she is saying is important. It is very much what occurred in this thread . I also think that by and large what people view as political and social discourse is often exactly what she describes. A speakers park with folks ranting from their various soapboxes oblivious to the others in the park ranting away or in this case hearing some one say Marijuana and jumping up to state their thesis on Marijuana be it legalization, spiritual use, doorway to other drugs or that all the pot smokers I know are lazy bums. Goodonya, Mary for pointing this out.
That being said, Mary's comment gave me a lovely image of Mary (and I don't know Mary so it was actually a short fiery spirited women with dark curly hair) stepping up onto a soapbox and proclaiming vehemently against soapboxes and their evils. While that is not her intent, it is the image it brought to mind. A cartoon that made me smile.