Complex sentence: In essence, the question of value-free design has been continually contested within graphic design between those who believe that design "can" be free from values and hence the graphics industries themselves should not be concerned with the underlying political questions.
Split into simpler sentences: In essence, the question of value-free design has been continually contested within graphic design between those who are concerned about the values in design and those who are believe design can be value-free. Those who believe that design "can" be free from values feel that the graphics industries themselves should not be concerned with the underlying political questions.