I think they are referring to pesticides that contain boron, and not specifically to the individual chemical component B(OH)3 (s), a.k.a. solid boric acid.

I can easily imagine a commercial pesticide targeted at ants and roaches that contains borates, sugar, and diatomaceous earth, because that is exactly what I use in my own kitchen, made from the individual components. It is effective, and has low toxicity to humans and pets. But to be clear, it is abrasive because the D.E. component is abrasive, not from the boric acid.

D.E. is actually the only powdered pesticidal substance I am aware of that kills via mechanical means.