“Western culture” to me, when mentioned by the English-speaking world, has really just meant the shared ideals of the metropolitan parts of English-first first world countries (that’s a mouthful).
This would include major cities in countries like the UK, USA, Australia, Canada and New Zealand but would also exclude their rural areas.
Not that I agree or disagree with it or that I’m trying to make a political statement - it’s just an observation I’ve found.