Maybe because Muslims hinder the social progress of a country?That question you ask your parent and my parent in 1991 I was kid in school, about Singapore that Chinese immigrant built it for his people ( the minority of island are Chinese) he was helping his own people and he did have islamophia and xenophobia ideas towards the Muslim( the ethnic Malay people). He was so blunt in his hate toward the Muslim.
Their refusal to integrate with others is quite proven in various countries. Always requesting others cater to their "religious beliefs"
Lee did make what Singapore is today, whether you disagree with his views or not