The dissolved light pillars formed light curtains that merged as they spread throughout the city, creating a layer of light over the basic defensive formation that is currently placed on a lot of stress due to the constant energy beams being fired from the bird puppets.
As soon as the energy beams struck this light curtain it was being diffused into a pure concentrated cloud of energy.
Even though the energy being light is a bit dangerous for people as that might lead to energy corrosion of the bodies, it is still better than being hit by the energy beams and anyway, the barrier formation is protecting them from these energy clouds.