Blackboard has, in effect, been a Moodle Partner for some time through it's acquisition of a number of existing Moodle Partners.
I believe (although I speak with no authority) that the agreement was to normalise and accept this situation.
Personally, I am two minds. This might well be beneficial to Moodle but (and I've said it before) all that patent bullying a few years ago made be incredibly suspicious of them. We'll see...