YTA, I suspect that was probably a pretty jarring and shaming accusation for your girlfriend to hear, and I really don't think you've been marginalized or oppressed by fetishization of British culture.

And, I think you know that because you seem to be coming more from a place of guilt or concern that your accent and culture are being favored over others'.

You may want to examine your own personal biases and insecurities here.

If it's any consolation, I'm American and I've been with my Indian husband for 13 years and I've always told him I love his accent.

...He's never responded the way you did, obviously, as evidenced by the longevity of our marriage, lol.