Every single business on the planet has a circumstance in which a single ill considered remark is cause for immediate dismissal. I can construct examples where nobody would expect the relevant parties not to be fired. eg calling the CEO a stupid [racially denigrating whatever]

So the argument you're really making is about whether what they did was sufficient to pass the bar for "should be immediately fired". Because it wasn't that bad? Because a little casual comic sexism never hurt anyone?