"I can’t think of a single time when the teacher caught it"
I suggest they probably did but like most teachers took a mixture of paracetamol, ibuprofen, cough medicine or imodium or similar rather than take the day off. As a teacher I can clearly recall lots off Ill staff between sept and January who came in regardless with perhaps a day off sick at their worst.
And really are we supposed to accept your memory as a parent that staff don't catch illness from students and infer that they won't catch covid 19 either.
"I worked with children for fifteen years (at close quarters) and I never caught anything but a case of ringworm when I was a student, despite them being little disease carriers."
Lucky you. I don't see how this little anecdote is relevant to covid 19 transmission.
"Let’s try to be optimistic and say that maybe, just maybe, with a bit of caution and wariness"
You seem to be implying that worrying about the health of colleagues and the lack of ppe or SD is irrelevant and blind optimism is all that's necessary to successfully open schools. You then further imply that teachers simply need to be cautious and wary to avoid infection which I find offensive. I can be cautious in the supermarket but other people breach the 1m rule all the time and I doubt teenagers will be any different because they certainly weren't in the summer.
If you think about it carefully, that maybe, just maybe your inane platitudes will provide absolutely zero protection for anyone working in a school.
I've already had a colleague lose both parents. If only they had maybe, just maybe shown more caution and wariness would they still be alive? Would you imply that doctors and taxi drivers needed to be more careful? I think better prepared ppe would have made more of a difference.