I'm curious who is saying that shotgun mikes shouldn't or can't be used for relatively close pickup. The only "shouldn't"s I've seen here (and posted myself) say that at significant distance, like in the diffuse sound field, they don't behave at all the way that people apparently wish or imagine that they would, i.e. as if they were telescopes or zoom lenses.
But when they're placed so that most of the direct sound arrives on axis, and isn't competing significantly with delayed versions of the same sound arriving from off-axis, they behave like ordinary directional microphones with some filtering out of high frequencies from off-axis. That's exactly what they're designed to do. It's also why when they're used on film sets (especially wide shots), someone with a lot of experience is working very hard at all times to get them as close to the talent as possible, and to keep the talent on axis as much as possible.