Why both political parties attract ideological extremists? . It is the system . but it is not set up by the Constitution

Ever ask yourself why both political parties attract ideological extremists? It is the way the US system works. It is not set up by the Constitution but has developed over time and is set in sand by state and federal statutes and Supreme Court decisions. It does depend on the protections afforded by the First Amendment and the Voting Rights Amendments. It is unlike the parliamentary politics of Europe, where ideology is the identifying brand of political parties, and coalitions form the majority, and voters have a branded ideological menu to choose from. In the US, extremists in our representative two-party gerrymandered system have to coalesce at the primary stage and support the party with which they feel at home, or otherwise they have no input into the system.

Neo nazis and white supremacists have found a home in MAGA. Socialists like Bernie Sanders caucus with Democrats even tho they are not the majority of the Dems. The quandary is where do libertarians and pragmatists, and those who care more about cultural, racial, religious identity, business advantages, or family affordability go who are not ideologically self-identifying or party or political leader loyal? Midterm and presidential elections are where the sorting eventually and finally takes place in one of our two parties