"I feel it is reasonable to have an explanation"
So do I.
A transparent and honest explanation, not just a "promise, we didn't do nuthin' wrong" explanation.
In any case, when you are root certificate, you should be above suspicion. That does not mean you shold not be suspected, it means you should do everything, continuously, to prove that there is no need to suspect you.
TrustCore has failed on that count, so its status as root cert should be revoked.