Or they just take the more nuanced JS Mill view that free speech is about truth and not simply about being able to say whatever you want without any consequences. Being offensive for the sake of being offensive has nothing to do with finding truth, so isn't perceived as a question of free speech.
Truth is not considered a defense to the crime of "causing offense" in the UK. Besides, the official standard of what's considered to be "truth" as opposed to "misinformation" is often skewed in ways that are entirely self-serving.
Of course, because we also consider intent, so the law distinguishes saying something true that someone happens to find offensive (which carries EHRC Article 10 protections), as opposed to saying something to cause offence that also happens to be true (which does not). If you're worried about a compromised judiciary one day interpreting such a distinction unfavourably then it's pointless because by that point they can interpret any law in a way that silences critics of the regime. Navalny was officially in jail for embezzlement but no-one's suggesting we shouldn't have embezzlement laws on free speech grounds.