The reality is NWBO is small potatoes in the overall scheme of things. The SEC is after bigger fish. There needs to be no other explanation than that.
If NWBO gets the case past discovery the SEC might start to pay attention. If NWBO gets a civil result the SEC will no doubt look at that and consider bringing a case against the civil defendants. If the SEC can develop a case they will refer it to the DOJ for prosecution if the SEC can't get a consent agreement that it likes.
The SEC has no criminal authority. All it can do is levy civil fines and those only if the entity agrees to the fine, otherwise the case goes to the DOJ for prosecution.