You got this backward. The UK and US announced they would send depleted uranium rounds to Ukraine, and Russia lost its shit (Reuters, NPR, NBC, Al Jazeera). Why do you think Russia lost its shit? I think it's pretty apparent it's because they don't want the West supporting Ukraine and will latch onto any issue that could weaken that support.

Western media lost its shit because media profits from sensational news no matter how stupid it's inferences are.

Western government media outlets lost it's shit because deplete uranium is far more effective in penetrating tank armor, and they had the tiny radioactive footprint as a focal point to cause a bit of fear based mischief, as governments do.