People just refuse to learn how lastfm works, don't they? Anyone can add whatever tags to any artist, track, album. But tags start to really matter when more people add the same one, that way a tags gains weight. To add a tag, lets say soul, even though soul is already added, makes it gains more weight, becomes more important. So if u think the dubstep tag is utterly dumb, add the tags that matter urself, when more people do that, dubstep gets a lot lower on the list.