@karen_cranston would be the one to comment in detail. There were so many bioinformatics organizations applying (which is a great thing, and a remarkable change to when we first participated) that they needed to reject some organizations that had participated in the past in order to make room for new ones.
FYI, Google has regularly shuffled things up - many large and very prominent organizations have failed to get accepted in some years. For example, OBF was rejected last year, but got in again this year. The Perl Foundation was out in the past and is in this year. The R foundation is also out this year.