And if you haven't gotten an application from one to do so, no need to go out of your way to have one.

If they had rejected someone for being black/asian/a woman/all the above, I would have understand the outrage. But in a field where 99% of the people active are white males in Britain, it makes less sense.

Should a conference about confucianism in China also find a western person to speak, or be cancelled?

Here's a quick quiz for you: name a woman/asian/black person that is active and does interesting things in the Python community? Here are the people that come to MY mind: 1) Guido, 2) Alex Gaynor, 3) Jacob Kaplan Moss, 4) several more white geeks.

Whereas in, say, web design circles I know far more women that do interesting things.