1. Because bond is frequently based on ability to pay. The more liquid assets you have available, the higher your bail or bond may be.
2. Because he surrendered his first passport to ensure he doesn't flee the country. Technically, by still having what I assume is a second valid passport, he can still get out of the USA.
Of course, all his actions so far show that he is not much of a flight risk. He cooperated with the investigation to start with. He turned himself in voluntarily as soon as he knew that he had to.
He has virtually no criminal history and has been a productive citizen.
This is all politically driven.
The only purpose of a bond is to insure that the person show up in court.