Granted, Ananias and Sapphira were entitled to give as much or as little as they wanted, but their motive was bad, and their actions were dishonest.
חנניה ושפירה יכלו לתת כאוות נפשם, אם מעט ואם הרבה, אבל הם פעלו ממניעים פסולים ובחוסר יושר.