I had retired before lockdown, so was only doing occasional bits of supply. Given the advice re the vulnerable, I stopped doing supply a fortnight before lockdown in order to shield my late husband.
I'd already lost a child to my job. There was no way that I was going to lose my husband to work too.
I know that teachers with certain medical conditions or with family with conditions were reluctant to go in, given what we were told about the need for distancing.
Newbuild schools in my area have tiny classrooms for some subjects and no opening windows - a significant problem at any time.
Nevertheless, schools here stayed open for the children of frontline workers and for vulnerable children - at least in my area. Teachers took it in turns to man the schools while those who needed to shield provided the online work.
I can't imagine that the parents of physically vulnerable children would have wanted their offspring to go into school.
As for the complaint about pushing for children to wear masks everywhere - surely that's something that should be taken up with the medics and scientists if you think that the advice was wrong?
After my husband died I returned to supply. I recall that both vulnerable staff and pupils were wearing masks to school. Indeed, I still see some children and a handful of non-teaching staff choosing to wear masks.