The birth rate in Switzerland (just as in many highly developed countries) is already way below 2.1 children per woman, which would be required to sustain the population. Any population growth comes from immigrants. Xenophobic people are scared by that.

Sorry, but it’s not xenophobic to care about your culture and not want it to shift too fast. The left’s inability to grasp this is part of why right populism has taken hold all over the world over the last decade.