I feel that while the author shouldn't be the arbitrator of what the whole work is about, they should have a say in what it's not about. e.g. if Lewis Carol would have stated that Alice in Wonderland is not about drugs; then the public should respect that and stop telling everyone else that it is. Following that thought to its logical conclusion, if extremists of any kind praise a work for promoting their view while the author denies that it does; with whom should we side?

I do think there's an interesting discussion to be had about it.