It seems you have a very superficial understanding of islam and secularism. Pathetic really. What do the US president has to take oath off- the uphold the constitution of US which is secular. Liberal Secularism itself is a religion with its own doctrine and principles based on individualism , sovereignty of men and yes defacto opposition to everything religion and in today's world that's Islam since all other religions have been lobotomized into a degraded version of liberalism. US presidents are secular . Don't they make it a point to state that - "
my religious beliefs do not influence my decision in office" . Saying anything otherwise is political suicide and social taboo. Can there be a US president who is openly anti-LGBT or anti-abortion?
Look at UK - the mayor of london had to denounce Islam publicly to prove his credentials for mayor's office:
https://defence.pk/threads/tolerance-and-the-first-muslim-mayor-in-europe.431167/
A bearded muslim with orthodox islamic beliefs can never be mayor of US , UK forget presidency or PMship and neither can a sister in niqab be an MP or congressmen.
Having state religion islam or religion of president are just symbols designed to placate the muslims of post-colonial muslim states while their leaders serve western interests . What's the point of having state religion islam if niqab or hijab is banned or imams are made to read out goverment approved sermons? Egypt's state religion is Islam with a zionazi sisi ruling them and placating Israel. Its pure joke and mockery of muslims in their own lands.