Polarization

The US is remarkably polarized, which leads to a public debate that is equally remarkably immature/unsophisticated. Two of the many reasons...

Winner-takes-it-all => Two-party system
This marginally democratic system fuels polarization. In a parlamentary system, a wide range of views and approaches are represented, and representatives learn to work together. Just about any citizen can vote for, and in most cases, see someone elected, whose views they share and believe in. Not so in the US, where many (the majority?) feel they do not have a candidate to vote for who accurately represent their views. It leads to a polarized debate and situation.

Corporate influences
Corporations control most of the media and politicians, and have an interest in a system that in effect is not democratic but have only the appearance of a democracy. It is in their interest to set the agenda for the public discourse (as they do), focus on issues of less importance, and trivialize or leave out of the discourse the deeply important topics. Polarization is in their interest as it fires up emotions, which can then be targeted on the "safe" (for them) issues (such as who of two presidential candidates - who both happens to support increased military spending and corporate globalization - gets elected).