The article says boric acid (used for cockroach as well as ant control) is relatively safe for humans, cheap, effective, and “it kills in so many ways that there’s never been resistance to it."
Next line "Some authorities think there never will be."
It's still possible they'll get resistant one way or another. The article claims 10% survived. This doesn't mean they're resistant to the dye/boric acid, it probably just means they never tried the bait. It's possible they'll become resistant to the bait (i.e. the bait won't attract them anymore).
