I haven't actually seen any sort of porn or drug transactions using BTC... there was the guy that talked about sending heroin, but that was just a thought experiment. Going back to the original comment that you quoted, I feel that what both you and creighto are saying is self-evident. I wouldn't expect walmart to use bitcoins unless there was an economic reason that didn't make them look like pedophiles/drug dealers/bad people. To me, you might as well be saying that the sky is blue.
I specifically used the example of Freenet, which does have problems in terms of trying to sell its use outside of the guerrilla applications like child pornography and Chinese dissidents. This isn't saying that "the sky is blue", but pointing out a major and significant problem in most peer to peer network. There have been numerous other articles in mainstream press articles about peer to peer networks that continually criticize the subversive nature of those network and dismiss the inherent benefits from such networks. This has become so large of a problem that at least proposed legislation has come in some areas to simply ban the concept of peer to peer networking altogether.... and that is something formally being pushed by groups like the RIAA and MPAA.
It is for this reason that I'm suggesting that Bitcoins try to at least philosophically distance itself from such subversive activities and try to stick with "legal" approaches and applications of this kind of currency and keep those kind of subversive activities more on the fringes of the group rather than a part of the mainstream of applications. Besides, there is no way to really know what kinds of activities have been done with Bitcoins, and certainly no statistical data to show there hasn't been "any sort of porn or drug transactions using BTC".
What I am saying is that shouldn't be the first kind of thing for somebody visiting this website. If I load up Freenet and give the mouse to a boss or CEO in a presentation about the technology, I certainly would be afraid of having something come on the screen when random links are pressed that would kill the presentation and make certain that its adoption would never happen.... even if I was not fired immediately for the presentation. It isn't simply saying "the sky is blue" but to me a very real concern.
One example of perfectly legal use of P2P is downloading purchased software. I downloaded torrents of both WoW and entropia universe because they downloaded faster and more easily than trying to download the software from the company directly. I got the torrents off of the company website. I don't know how many other companies offer torrents of their software, I expect it would encourage piracy for those companies that charge for the software itself instead of for license to access their servers, but I know that just the traffic downloading WoW is enough to hold up as a significant legitimate use of a P2P network. I believe they also torrent their updates.