nobody should frown upon another person for leaving their house with covid to go run unless that run involves being in very close contact with others for an extended period of time. Which for most runs is not the case.
That depends on how many times you trip, fall, have a heart attack, get mugged or raped, use a public toilet, or any other random non-zero chance social and/or hospital interactions more likely to occur when you run outside vs. shelter in place.
But I don't have the impression anyone cares as much at this stage. It was more of an issue when we didn't have vaccinated folks and everyone was walking on egg shells trying to prevent our hospitals from imploding.