For a single didactic example-- someone with diabetes walking in to pick up a take-out salad from a bar filled with unmasked people is normally a very low risk activity.
That same activity in a pandemic where percentage positive is approaching uncontrolled spread is prohibitively risky.
Am I missing a hidden premise here that's causing you to dig in your heels? It feels legitimately odd to need to explicitly defend the idea that there exist inescapable negative consequences for the wider community when a critical mass of people actively shirk their responsibility to be safe during a pandemic.
Edit: clarification
Can simply not do that in the current high risk environment. There are plenty of places offering take out food that don't require you to go into a room full of unmasked people to pick it up. So voting with your wallet seems like a perfectly viable option to incentivize businesses to take proper precautions and ensure that their customers do.
Also, are you assuming this person with diabetes is properly following all the guidelines? Are they wearing an appropriate mask, and wearing it properly (covering both their mouth and nose with a good seal all around)? Are they washing their hands right afterwards? (Or wearing gloves--my wife and I do that in cases where we can't be sure about whatever we're going to have to touch.) Are they minimizing the time they spend in enclosed spaces that aren't their home? Those are all things you can do to mitigate risk in situations where you have to go somewhere, such as the grocery store.
> It feels legitimately odd to need to explicitly defend the idea that there exist inescapable negative consequences
They're not "inescapable". That's the point. If you know you live in a society where a lot of people are not taking proper precautions, then you can take that into account in planning your own life and taking your own precautions. My wife and I have been doing that since the end of February 2020. It's doable. And since it's doable, I don't buy the claim that there are "inescapable" negative consequences.
How much of a risk, compared to all the other risks we all undergo every day?
Also, how much of the risk is not there if you really, truly follow the guidelines? I see a lot of people who might think they are, but they're not. They don't wear their masks properly, or they wear a loose weave cloth bandana or scarf instead of an actual mask. They don't actually social distance--for example, I routinely see people in the checkout line at the supermarket not even making use of the 6-feet-apart markings that the store has put on the floor. They don't avoid crowds. They don't minimize the time they spend in indoor spaces that aren't their home.
In other words, you don't need a hazmat suit to mitigate the risk. But you do need to pay attention to detail and understand what properly following the guidelines actually means.