The poster is saying that, short term, social change (immigration or political upheaval) brings about a reaction in favor of what is seen as conservative or har

The poster is saying that, short term, social change (immigration or political upheaval) brings about a reaction in favor of what is seen as conservative or hardline traditionalists. In many European countries this is a shift to the right. For example Hitler's rise to power was probably aided by Communists attempting to seize power. I'm not sure this is a general rule.