Baseball bats weren't designed to be lethal weapons either, but are definitely deployed, without training, in cases of self defense. You can, should, and will use any advantageous object in service of self defense; it's that simple. And sure, things go wrong sometimes, but it's believable that anyone is calculating their efforts to improve the odds of justice, even if it is not always perfectly served.
Baseball bats weren't designed to be lethal weapons either, but are definitely deployed, without training, in cases of self defense. You can, should, and will use any advantageous object in service of self defense; it's that simple. And sure, things go wrong sometimes, but it's believable that anyone is calculating their efforts to improve the odds of justice, even if it is not always perfectly served.