>>> Why has Australia been subjected to Islamic terror?
Operation Okra, perhaps?
https://en.wikipedia.org/wiki/Operation_Okra
>>> Why has Bali (in the muslim country of Indonesia) been subjected to Islamic terror?
Perhaps because extremists see 'not being Muslim enough' as at least as bad as, or worse than, being 'Crusaders' (as ISIS often refer to Western countries in their statements)?
[i.e. moderate Muslims, who don't conform to the strictest interpretations of Sharia Law, are viewed as 'infidels']
>>> Why have the Philippines been subjected to Islamic terror?
Amongst other things, it's to do with a desire for independence for Bangsamoro, which was rejected by the Philippines Congress, with the (Islamic) Maute Group supporting that cause. (i.e. it's far more to do with politics than religion in many ways, much as the Catholic/Protestant struggle in Northern Ireland was really far more about political differences than religious ones)
>>> Why were 20+ coptic Christians murdered in Egypt by Islamists this week?
Probably because extremists regard Egypt as an Islamic state (which, indeed, it is, as the country's constitution requires all legislation to conform to Islamic law) and they reject anything which they see as 'watering down' the influence of Islam within their country.