Why hasn’t Twitter flagged the Islamic derogatory term ‘kuffar’ (filthy unbelievers) as hate speech against all non-Islamic religious groups?

https://barenakedislam.com/2020/06/28/why-hasnt-twitter-flagged-the-islamic-derogatory-term-kuffar-filthy-unbelievers-as-hate-speech-against-all-non-islamic-religious-groups/