The only reason why spam cancellation is accepted is that the spam definition completely avoids confering legitimacy or lack of it on the content. Everything is legitimate in at least one person's eyes. There have been many times where I've agonized over the fact that some bit of material is for something I consider highly legitimate, but, it hit the spam thresholds. If it hits the spam threshold, it has to go. However, that would only serve to loosen up the definitions such that spammers would be able to get away with far more than they do already.
Most people already consider the spam thresholds too high, rather than too low.