Compare the policies of the Democrat party with those of the Conservative Party in the UK. The Tories are left of the Democrats, that makes the Democrats a right-wing party and the Republicans further out than Genghis Khan.
It is the same in other '5 Eyes' nations such as New Zealand and Australia. Our right wing parties (National & Liberal/ National Coalition respectively) are left of your so-called left-wing party.
The USA is the outlier, not everyone else.