I don't think it's meant to imply a conspiracy, rather that lab safety around novel compounds is probably not as tight as people assume it is. I will put forth

I don't think it's meant to imply a conspiracy, rather that lab safety around novel compounds is probably not as tight as people assume it is. I will put forth another (possible) explanation: fake sugar has to be widely marketed, and "we were doing Important Science when we accidentally discovered this fake sugar" is a more marketable, easy-to-understand story than "we added/removed groups on a range of compounds determined likely to be sweet based on a literature review, in order of how amenable the reactions are to mass production, then tested each of them in rats".