Comparing the US system with parliamentary governments - I reject the assumption that the two parties are clearly divided along left-right lines. People all have a pretty wide diversity of opinions there are plenty of people I know that are both pro-life and pro-medicare for all - they don't have a home in the US political system and thus have to settle for one party of the other.

The US's two-party entrenchment forces this false appearance of an us vs. them political battle. It's true that in the US you can only legitimately vote for either D or R in races and that this further entrenches the two parties - but issue voters should be flowing pretty freely between the two parties as their individual focuses shift.