It was not my intention to come across that way. The person I was replying to took the position that diversity should be a huge focus when choosing the speakers

It was not my intention to come across that way. The person I was replying to took the position that diversity should be a huge focus when choosing the speakers. I don't know whether or not minorities were considered in the first place, but if they were and none were chosen we would still be sitting in exactly the same position. I have no doubt that there are loads of great minority Ruby developers, but that doesn't necessarily mean they live in London, are available on the given day or are interested in conducting a presentation. I don't think it's entirely implausible that the hosts chose their speakers fairly and ended up with this selection.