If the writing offends you it accomplished it's goal. Keep in mind that druids are supposed to be about upholding some natural order of sorts, and planetouched people, like tieflings are very much an anomaly to the natural order of the prime material plane. Sylvanus and druids in general are not about being fair, being just or even being nice, so I don't see why they wouldn't be hostile to a bunch of demon-looking creatures who have flames for eyes and steal their stuff. Appealing to modern sentiments of "human rights" makes no sense because tieflings are not humans, Kagha is not human, in fact we are talking about species that are only connected via their ability to interbreed. This doesn't mean that suddenly everyone is just another flavour of human.
Furthermore you could argue that the idea of "equality" or "human rights" are a product of civilization, so druids could be explained to be naturally opposed to that.
Just my two cents.