I wonder if this degradation could also be a health risk, as many polymers are hydrocarbons, which do have known health risks.
Would you consider wax and vaseline as "health risks? Or mineral oil? Those are basically polyethylene but at much lower molecular weights. The hydrocarbons you're probably thinking of (octane and below) are even lower, but e.g. propane and butane aren't actually particularly toxic.
I would consider anything we didn't have in our environment until very recently a health risk, simply because it's a form of "testing previously untested inputs in production"
Edit: To be clear, in the context of evolution, I would eyeball "very recently" at about 100,000 years.
If it takes a long time to have an effect and is linked to many other comorbidities (as will be the case for obesity at least).
Waxes are a huge category. I would guess some do and some don't. Beeswax for example has 300 chemicals in it, some may be beneficial and some could be harmful.
Vaseline is supposed to be largely safe. There are various grades of petroleum jelly, some of which could be carcinogenic.
I would far more trust a new substance that has been tested thoughtfully.
I would prefer older substances that have a large battery of testing. This time also allows some group-think or other new product bias to dissipate.
Humans have evolved to cope with lactose and alcohol. Getting sick is that response. This is the same in how we've evolved to live with fire. Not because evolution can magically make us invincible to chemical combustion -- instead we have pain receptors and learn to avoid it.
Some 20k years ago, some of our ancestors started consuming milk even in adulthood, and it turned out a few of them had a mutation that allowed them to continue producing lactase even in adulthood. Since milk is actually a very nutritious substance if you can farm it, these people thrived and passed on their genes, in some areas.
I was thinking more generally: "someone drinks milk, they get sick, they don't drink it, don't die".
In the case of alcohol, our body detects the alck of balance and other neural impacts, classifies this as a poisoning, and it tries to provoke vomiting to eliminate as much as possible of the poison. It's explicitly an adaptive response that we developed to survive consumption of poisonous substances.
Our evolutionary ancestors could’ve involuntarily consumed alcohol way before 20k BC.