Bats are actually quite a bit less dangerous than a lot of people think they are, thanks to a long history of misconceptions, superstitions, and just flat-out wrong information.
For starters, the grand majority of bats don't suck blood (and the ones that do are native to South America). In fact there's quite a few species of bat that are vegetarians! These ones feed off of fruit and nectar.
Even the ones that are carnivorous tend to mostly eat insects, and they actually do a great job of keeping the populations of insects like mosquitoes to a minimum! Just like spiders, they may be a little scary, but they do a lot of good!
However, one thing about bats that is a legitimate danger to humans is the fact that they can carry rabies, which if threatened, they can transfer to humans through a scratch or a bite. While you shouldn't be scared of bats, you should still keep your distance from wild ones.
So of course, when a bat gets found somewhere like an elementary school, there's instantly some concern about people's safety.