Gazebo gravity is switched off for whole robot

Hi, is there a reason why this model turns gravity off for gazebo?

https://github.com/clearpathrobotics/LMS1xx/blob/d80907e539d72a373002e9d68e4b982eb4b6d7ce/urdf/sick_lms1xx.urdf.xacro#L58

This is a problem for robots which include this sensor because gravity gets turned off for the whole robot.
(see this issue: https://github.com/husky/husky/issues/181)

Kind regards!