OP doesn't really understand that outside of the US people are more than black, white and Asian. It's not that long ago that the chairman of one of the most powerful German parties asked the population to report people if they hear them speak Arabic.

In the US whether you're Arab, Turkish, Greek, Iranian, etc. unless you're one of the darker Arabs they're all seen as white Caucasian to the average Joe. There was a report not long ago that people with Turkish names are half as likely to get a job in Germany. So the average Joe wouldn't understand that places such as FOSDEM are very diverse and very welcoming to any one of those backgrounds.

There was a blog post complaining about the lack of diversity at FOSDEM a couple of years back. Everyone was thrown in the "white Caucasian male" bucket. But that's less a testimony of FOSDEMs diversity and more one of the ignorance of a certain demographic that likes to look at the world through its own lens.