I agree that there are ethical concerns around animal products, and I can see why you would try to DIY your way out of those concerns, but animal welfare isn’t the only ethical concern in the world. Deliberately, knowingly circumventing fire safety standards puts you and others at risk, and that is a pretty non-trivial ethical problem of its own.
It’s somewhat dispiriting to see somebody specifically acknowledge that they know what the wool or synthetic materials are there for, then completely fail to address it.