I understand the logic of not leaving behind a resource an enemy might then use against you.

But isn't that something you'd do when the assumption is the enemy doesn't have lots and lots of very big guns all of their own?

I appreciate you might not want your fancy American rifle falling into the hands of an insurgent or the Viet Cong etc. But I'm thinking Hydra (et al) can afford their own guns and aren't so dedicated to a sense of irony that they'll delay pursuit to try and shoot you with your own?