What makes a man apparently plan in cold blood for two years the mass murder of his fellow human beings, in this case based on their religion and their status as immigrants in a Western country?

Clearly you are not a normal, well-balanced human being – there are no indications so far the shooter is mentally ill in any way – but it’s for psychologists to debate what parts of your humanity must be sufficiently broken, and why, to enable you to commit an atrocity like this.