Just because the Democrats are the most left leaning party available to Americans doesn't make the democratic party a left leaning party. If anything the Democrats are centerists because their ultimate objective is to maintain the status quo. Lemmy reaches to far more countries that just the United States, places that have left leaning parties. Even left-wing extremists parties, although they're definitely on the ropes lately.

The Democrats aren't a progressive party, they're a conservative party. It's just with MAGA in the room the scale has moved so far to the right that the center (conservative) seems progressive.