I think most people lack an understanding of basic chemistry, for example If i was against sodium or "salt" I could be as wild as to say
"omg dont use salt, its got ingredients known to be in euthanasia!" aka "Sodium Pentobarbitol"
Just because a product may contain a similar chemical/element does not mean it has the same properties or reactions, being of a different compound makes a big difference, I mean look at the difference between CO2 and O2.
I personally believe the play on each others lack of understanding and leading them to conclusions to fit their beliefs is kinda sad really.
ETA: The difference between CO2 and O2 is one can help you live, the other can help you die, yet they are comprised of almost the same elements, only... the CO2 has an atom of carbon in it, which vastly changes its properties, reactions and volitility
catch my drift?