This may be true but I hate the practice of referring to "plastic" as if it's a single substance. It's a bunch of different materials that don't really have that much in common with each other, especially from a health/toxicity standpoint.
For example, people treat it as common sense that "you shouldn't burn plastic" because the smoke is "toxic". For PVC this is totally true, it makes very nasty stuff like dioxin that will poison you. But on the other hand you can burn polyethylene (think milk jug) and it's no more toxic than burning a candle. Definitely way healthier to breath than wood campfire smoke, for example.
There's also such a silly pattern where people learn some chemical might have some effect on the body and suddenly everyone is up in arms about it. For example Bisphenol A in many applications was replaced by the very similar Bisphenol S just so things could be labeled "BPA Free". BPS probably has similar estrogenic effects to BPA.
I'd say the moral of the story is be wary of received wisdom about chemical toxicity from people who aren't chemists.