to get the energy needed for a laser that can burn stuff ,the high energy light of bleu is required ...
doesn't mean they can't do it with lisser energy dense colors in future ... but as seen in Hawaii ,they clearly used the technology that uses the highest energy color ,blue ,thus perhaps they don't have the other harder to create technology yet ,or they just don't want spend more money on thse laserts because of their arrogance that the idiots of earth won't figure this shit out anyways.