This is absolutely fantastic! I would have chosen psychological research instead of the Dalai Lama to bolster each of these points, but...actually...every one of the "spiritual principles" is affirmed by psychological research, so this way works too.

It would be even better if you had some suggestion for the last step in addition to "admit racism within yourself".

Firstly, but less importantly, I don't think it's well-established that literally everyone behaves or thinks in a racist fashion. If there is anyone who actually doesn't, then they have nowhere to go at the end here.

Secondly, and more importantly, people who try very hard to act in a principled way may find it difficult to embrace humility to the necessary extent. Are they really powerless to sway Cameron until they do? I would hope not.

Psychology research provides some clues here (e.g. appeal to empathy, dignity, etc.).