Complex sentence: First, they insisted on placing movable chairs in the park, as per Whyte's long-standing belief that movable chairs give people a sense of empowerment, allowing them to sit wherever and in whatever orientation they desire.
Split into simpler sentences: First, they insisted on placing movable chairs in the park. Whyte had long believed that movable chairs give people a sense of empowerment, allowing them to sit wherever and in whatever orientation they desire.