It doesn't bother me as much as it once did.
It's when I for examples:
Hear a table full of thais in a restaurant saying bla bla bla farang bla bla bla farang often accompanied by laughter or not that makes me think to myself don't these people have anything better to talk about.
Getting in a minivan in issan and standing out like dogs balls. Mum hands phone to toddler who's 30 second conversation to dad on other end goes something like "dad theres a farang in the van".
News readers usually use the correct term chao dang chart but when they use farang to me it makes them seem kind of scummy and unprofessional.
However to answer the question I agree with ChatGPTs answer below:
It is a curious thing indeed! Some foreigners in Thailand call other foreigners farang for several reasons:
Assimilation – They adopt local speech patterns after hearing Thais use it often.
Convenience – It’s a simple way to refer to other Westerners when speaking with Thais.
Jokingly/Ironically – Some use it playfully, aware of its usual context.
Exclusionary or Derogatory – Rarely, some long-term expats use it to distance themselves from "tourists" or newcomers.
It’s mostly harmless, but how it's said matters!