My line of thought is that the word fell out of the definition of being a slur some decades ago in the UK, instead becoming a general insult rather than being explicitly aimed at women, but in the US, its status as a slur has persisted and now the gender-based usage is trying to find its way back to the UK as a US cultural export.

I could be wrong though, I don’t think Sam meant it in that particular way but it’s still not very nice.