Toxicity isn’t as simple as “toxic = toxic + toxic.” While some byproducts of plastic breakdown are toxic, the bacteria are further dissolving those as well, going until they get glucose, as they wouldn’t be able to eat it if that wasn’t the end product. There are probably still some toxic byproducts that get excreted rather than broken down, but plastic breakdown already releases toxins under normal conditions, so that’s already a problem we’re going to have to tackle. If these bacteria can get past the first issue of breaking it down in the first place, then that’s a net positive.
Yeah, it’s specifically because they’re trying to increase profits for so long that they need to get so incredibly meticulous and complicated with how their business works. Companies that just try to earnestly provide a desired service to people who need it in their area of operation don’t need to worry about such details.