I know the headline is funny and the article really undersells it, but this is genuinely a really easy thing to do. Carnation poppies are a popular ornamental plant, bread seed poppies are a big part of some European deserts, and all of these types of poppies are the exact same Papaver somniferum. You probably have some in your cabinet right now as bagel seasoning or as a spice, and planting it might be considered a felony. Hell in some countries like South Korea poppy seeds in all forms even for culinary purposes are illegal because of this.

I imagine what happened is that a European seed company (where opium poppies are a common garden plant) sold this thinking that it would be OK because this subspecies has been altered to have lower alkaloid levels.