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)