It's irrelevant what the people here or elsewhere think -- as you say there are many dissenting opinions but very few professional legal opinions.
Rather than dally with opinions, let's stick to facts: The authorities will shut down sites with illegal activities and the authorities are aware of these subreddits. The authorities did not intervene.
Regarding your comfort with blanket bans, you may want to read this other article recently posted to HN which offers a much more insightful analysis: http://news.ycombinator.com/item?id=3585997
Rather than dally with opinions, let's stick to facts: The authorities will shut down sites with illegal activities and the authorities are aware of these subreddits. The authorities did not intervene.
Regarding your comfort with blanket bans, you may want to read this other article recently posted to HN which offers a much more insightful analysis: http://news.ycombinator.com/item?id=3585997