Ultimately this is not about race, and not necessarily about culture but about Values and Beliefs.
I accept that they are often associated but they aren't inextricably connected.
For example, some Muslims might believe that people who fail to follow the 'true religion' have lives that are of no value and would be better off dead - but many people from Islamic culture don't believe that.
Some people from other 'cultures' are like Dr Harold Shipman who seems to have believed that whilst helping most patients was the right thing to do, some of his older patients had lives that were relatively without value and would be better off dead.
We need to ensure that whatever cultural background people come from, the Values and Beliefs they have instilled are in tune with the prevailing values and beliefs that most people in this society have displayed for many years, tolerance in particular.
Anyone - from any culture - who is indoctrinating or encouraging Values and Beliefs that conflict with that should be marginalised and if necessary, excluded from positions that provide opportunity to influence others.