Personally I think SDC pulled out of Blocknet due to pressure from whale holders...  Yes we knew this much...  But the reason?

My thoughts are as follows.

The whales needed sole control of information to be able to properly pump and dump the coin for profits.  Being part of Blocknet relinquished some of that control to outside sources by way of the price of the coin being susceptible to outside price jumps or dips based on anything associated with Blocknet.  

Also, it dilutes the usefulness of their advertised anon function as XC already has a fantastic anon feature.  They specifically want to be able to milk this feature for all it's worth by having complete control of SDC features with no outside interference.  In essence they need complete dominance of SDC to rake in maximum profits.

That...  is my opinion on the matter.