DE has been the slug solution of choice for organic/sustainable gardeners for many, many years.
Certainly I would not want to inhale a lot of it every day. If you do that with damn near anything except straight clean air, it will do harm (dust, tobacco smoke, paint fumes, auto fumes, the air on Manhattan...just sayin.)
It's more about common sense I think.
And yes, DE will kill honeybees, and bees of all other kinds, so it's really important to use it carefully. It's still better than a chemical in MOST instances I think. Though not all.
But it can really help to reduce your chemical usage.
you just have to be careful where you put it, and with timing (like don't dust when the bees are working the blooms.
There's a lot of bullshit out there about DE, and based on some sites, you'd think the stuff will save the world and bring about world peace.
I found one site that is very general but isn't stupid.
SimpleGiftsFarm
I don't have time to dig up any others at this point, but a few google searches with different phrasing using the right keywords will net you a LOT of information.
It's a good tool. Just ONE good tool.
One useful thing you can do is search on the reputable bee forums for lists of the plants honeybees work.
(Of course, this doesn't help the other bees, which are just as beneficial)