"Yep. I know. Rather my point.That's why this is racism. Presumably if they were mocking religion they would do it in their own language.........."
Eh? You do realise most Muslims are not Arabic speakers? It doesn't make sense to mock Islam by saying 'God is the greatest', because Muslims - even white, English ones, who only speak English and no other language - don't say 'God is the greatest', they say 'Allahu Akbar', even though they don't speak Arabic.
There are some core Arabic phrases, such as 'Allahu Akbar', ' la ilaha illa'llah', 'bismillāhi r-raḥmāni r-raḥīm;, and others, which very clearly signal 'Islam', which their English translations simply do not.
Mocking Islam in English just doesn't work.
'God is the greatest' - whose God?
'There is no god but God' - ok
'In The name of God'
People wanting to mock Christianity would do so in whatever language they normally spoke, 'Our farter who fart in heaven' is comprehensible to an English speaker, but means nothing to an Indonesian Christian, but if you mock Islam using Arabic it's universal.