Media worried about a surge in "Populist Nationalism"

The left wing media are worried about a surge in what they label as "Populist Nationalism" ... pointing to rising the popularity of Winston Peters and NZ First. They also point to other conservative political leaders around the world, including Giorgia Meloni in Italy, Nigel Farage in UK, Viktor Orbán in Hungary, Australia's Pauline Hanson, and of course Donald J Trump. Why are they so concerned about a rise in conservatism around the world and in New Zealand?