It only just happened. From the language and timing it looks like a snap emotional decision rather than a rational one; I assume the organisers got blindsided by the negative feedback and didn’t want to deal with it any more.

ETA: “@Rebeccask Due to sexist & racist remarks made on twitter last night got way out of hand. Sponsors pull out. No money no conf” (https://twitter.com/Rebeccask/status/270220165344550912)

It's too bad that this 'no money no conf' meme continues to dominate. You can have something more than an 'unconf' or 'barcamp'-style event, even with no or minimal sponsors, especially with a team of organizers/planners to share any overflow expenses that do not get covered by ticket prices.

So you suggest that on top of volunteering time the organizers should also cover "overflow expenses" from their pockets? Sounds excessive to me.

Yes, I do suggest that. Perhaps not actually look at it as just 'volunteering' time, but 'organizing an event'. If there were actual profits (income-expenses), then sharing those profits with the people who made the event happen (organizers, speakers, crew, etc).