Bit of both, really. And the "perceived threat" is still relatively unknown (this virus is still being studied). Erring on the side of caution when the results can be the same either way is a prudent choice.
That said, we have made the decision to shift both of our kids back to in-person, as we're finding that the results aren't going to be the same. Just going to have to adapt as best we can. We're just fortunate we have the choice, and (hopefully) the ability to navigate it safely. Not everyone is so lucky on either front.
I think one of the things we will learn out of this is how little we know about how to effectively teach online. Our school meets in person from 8 to 1:30, then teachers go to online learners from 1:30 to 3. I really don't understand how the two are supposed to equal out.