I think the broader issue with this sort of choice in a pandemic is it does have downstream effects. People going to school everyday could cause an uptick in community cases that then makes necessary trips like the grocery store more dangerous for those who do want to isolate as much as possible. Especially relevant in a city where many people are living together in apartment complexes.
So I agree there's no clear answer here, and I think pre-vaccine I would've kept my kids home regardless. But more generally I am very dissatisfied with how homogeneous and inflexible the school system is, and that is something we should push for change in. Funnily enough, my district has done a full 180 since COVID and this past year stopped accepting doctor's notes to excuse absences! They are quite literally encouraging people to send their kids in even while sick. A friend's son has mono right now and the HS is threatening to hold him back over absences (grades are fine still because ofc that matters less than attendance record.