They are indeed valid questions, and the lack of actually answering the question says that they didn't know the answer but couldn't resist chiming in with a glib response.
We know how to make things that are lethal in incredibly small doses.
Compare to this, which is not likely to stay in the air well, not self-replicating, and not-contagious, and would require larger doses for lethality.
Sure, we should be careful with any new technology, but the options to weaponize this or to have unexpected bystander externalities seems really small compared to other established technologies and risks we bear.