Because as the third in the line of secession, He was fully aware of it Months ago!
I’m nowhere near any line of succession and I knew about it in January or February when it was all over the news.
The only new detail in the recent story is that the ransom was paid in physical cash. Republicans in congress, including Ryan demanded an explaination at that time. The story gained no traction and disappeared. Apparently nobody cared, until the fact that it was a plane load of currency came to light. Ryan has demanded an explaination all along, Obama has ignored him, as he always does.