My counter-apologetic for Christians saying "it's a metaphor/figure of speech."
When Christians are confronted with horrible Bible verses, a common Christian apologetic is to say that it was meant as a metaphor, hyperbole, or some other figure of speech. Examples: they'll say that genocide in 1 Sam. 15:3 is a hyperbole, and infanticide in Psalm 137:9 is a poetic metaphor, and Jesus calling for slaughter in Luke 19:27 is only part of a parable.
Of course we could argue all day about how it should be interpreted. We could point out how 1 Sam. 15:10-11 really proves that God wasn't just being hyperbolic when he called for genocide. We could also point out the arbitrariness of how Christians decide what is or isn't a metaphor depending on how convenient it is for them.
But for the sake of argument, let's pretend that it is just some figure of speech not meant to be taken literally. It still isn't okay, and here's why: metaphors and other figures of speech are ways of describing or explaining things, but it still matters how you choose to describe or explain something. It's still meaningful even if the meaning isn't literal.
For example, I'm a teacher, and let's pretend that I hear a fellow teacher refer to his students as "dumber than monkeys." I'd say, "That's a really disrespectful thing to say about your students!" And he counters with, "Oh but I don't mean that literally, it's just a figure of speech!" Then I'd say, "I know that you're not literally saying they're less intelligent than monkeys, but that's not the problem. Your figure of speech is still awful because literal or not, you're still calling them dumb. The problem is, why would you insult them like that? Why would you dehumanize them like that? Where's your empathy for them?"
And it gets even worse when the figure of speech could be taken as an actual threat. Imagine if a babysitter made a figure of speech about abusing children. You wouldn't hire that babysitter, would you? Imagine if a surgeon make a figure of speech about murdering you on the operating table. You'd want a different surgeon, wouldn't you?
The smashing of babies' skulls in Psalm 137:9 is still very threatening even if it is a figure of speech, especially in how it celebrates infanticide. When Jesus calls for slaughter in Luke 19:27, even if it is a figure of speech, it's still a violent one. When someone describes something with violence as if violence were a good thing, that really tells you something about their mindset.
Even if they were debatable figures of speech, they're still horrifying and no one should be okay with that.
And to be clear, if something is clearly meant as a joke, it's quite different. My friends and I share a lot of dark humor because we all know that we aren't being serious. But no Christian would dare say that the Bible isn't being serious. There's nothing in the text to suggest that it's just joking. So it's also not a defense to say that horrible figures of speech are okay because dark humor is okay; they don't have the same intention.