Why don't Trump or the Republicans ever want to know why Flynn lied?

Seems like a good question, right? You would think a president and his political party would want to know why the National Security Adviser would lie about things that were supposedly legal. But not Trump or most Republicans. They are totally alright with not knowing the answer to this question.

I heard somewhere that it's often what the guilty are not interested in that shows what they know. Could it be that Trump knows exactly why Flynn lied, and that's why it doesn't interest him? As to his party, are they afraid the answer is simply one they don't want to hear?