Why are cultural differences so destructive?

When the British departed, most reluctantly, from Malaya, the 4 Federated and 5 Unfederated States, plus 3 Straits Settlements, became the Federation of Malaya. The majority Malays converted the new nation into a Malay Muslim one. What of the other ethnic communities (including mine) which had contributed to the development of the nation? Ethno-tribalism ruled.
Expecting the Malays to eventually claim all the top official positions, and other jobs to be decided on the following principle – if a Malay can do the job, he should have it – I declined an offer to join the new diplomatic service. I based my assessment on what had happened in Ceylon, with its display of ethnic discrimination. The post-colonial experience everywhere was – ethnic minorities beware!
In Ceylon, the British handed over control of hitherto independent Hindu Tamil lands to the Buddhist Singhalese. Reportedly, their priesthood had successfully influenced the government to adopt the ‘Singhala First’ principle. This discrimination against the non-Singhalese, well-documented, led to claims of a degree of autonomy by the Tamils. The outcome is now deplorable history.
Before the European nations imposed their white Christian colonial supremacy over these lands, Indian Hindus and, later, Indian Buddhists had influenced these lands culturally. Now, majority rule under Western democracy led to unequal minority-community political rights. Pride in the ethno-religious heritage of the ruling tribe rules.
However, is any religion superior to all the others? Not on the evidence. Dogma divides, but does not bestow primacy. Is any tribal community different from all the others – in terms of human potentiality, religiosity, cultural pride, or individual proclivities? There can surely be no chosen people anywhere, since we are all co-created by the one and only God.
Since humanity is the same everywhere, at both its highest and lowest levels of behaviour, then surely it is greed for power which drives the control and discrimination over others; as well as the abdication of the underlying humanistic principles of the religion to which the guilty claim to adhere.
It is not culture which is at fault. It is the use of culture by morally faulty human beings, in both political structures and institutional religion.