Yeah mass isn’t the right measure, but it could just as well be expressed in metric units of volume, i.e liters. Barrels aren’t special when they express the same thing.

I think the reporter might’ve used the metric ton as a general expression of “a lot” in their head and meant to express volume. If metric system isn’t familiar to them, it might not be obvious that a metric ton is for mass and in general metric units use kilos for thousands.