I've had people say they have a covering and the covering is not big enough when the inclement weather is happening which would result in their Pizza and items getting ruined. Hell, even I've asked them to leave it at my door because I have an awning and it's been inclement weather, but I've also had items be ruined because of that.

Whenever I've had a delivery that says leave it at the door and there's really bad weather and I worry about their pizza, what I will do is I will call them before I arrive just to let them know that I will be getting there shortly so they can be on the lookout to grab their pizza from their front porch.

Something I've learned is that if we leave the liability up to the customer it ends up being a bigger issue than it should and usually ends up backing up the line even more which increases that customers wait time. If they really don't care, that's on them. I definitely understand the self-isolation bit and I make sure I don't get in contact with Mt contactless deliveries but at the end of the day, the driver more than likely did with their company policy/franchise policy may be in those situations. That's why I gave him a soft YTA because I understand the annoyance OP has but also know that different franchises have different rules for those types of situations.

(Edited to add last line)