I’m not particularly studied on the topic. However, what I’ve read was pretty convincing that the DU was a serious and confirmed factor in the ill health issues of the servicemen, their sexual partners, their children, grandchildren & great grandchildren. The government was not going to be unnecessarily on the hook for many billions of dollars for no reason.
Of course they could be, pseudoscience, AGW anyone? Why then is the mil still using DU projos?