If you're worried about your headphones, wait till you start thinking about the fabrics you're wearing that have plastic in them.
If I was going to try and limit exposure I'd start there, my headphones wouldn't be high on my list.
BTW I don't know anything about the subject, so I mainly look for internal consistency and specific, accurate factual claims as evidence for credibility.
I'd much rather they focus their energy on the more ubiquitous sources of exposure to endocrine disrupting materials in our environment (plastic packaging, plastic bottles, can linings, mattresses and clothing for example).
There's no harm in sharing information and any awareness gained is always worthwhile. We're all free to draw our own conclusions at that point.
Apologies for the confusion on that aspect.