Roleplaying is ENTIRELY about consensus. I suppose if you really can't handle the very plausible and entirely supported by the real world idea that an isolated population might develop a tolerance (and that's all it is, not an immunity) to something that is toxic to humans, then I don't really know what to say.
If this is considered unacceptable then, surely, anything that isn't strictly outside Canon is not allowed. Heck, why aren't you telling me that my Civire can't be a Tube Kid? Heck, for that matter, every single character bio in the whole community is non-canon and should be disregarded!
I understand some people's reaction to Caldari RP. The State is basically predicated upon identifying social groups as outliers or inliers. Their language uses suffixes to underline this difference between the three levels of outsider, fellow State citizen and close workmate. This often comes off as cliquey and the use of an 'incrowd' language merely reinforces this. It is supposed to. It is devised for that purpose.
Every culture is more or less problematic when it comes to playing across borders. The Gallente tend to be patronising. The Amarrians have this whole 'manifest destiny' problem. The Minmatar have an enormous chip on their shoulders. The Caldari are cliquey and isolationist. THAT is according to canon.
If it really annoys you, make up something that only Nefantar can eat and try and get THAT adopted by the community and stop being a negative nellie.
