historically left wing organized political resistance has been much more organized and restistant to internal fractured and infighting. right wing organized movements (think the dozens of nazi groups that have cropped up and then killed themselves off with no outside help) have been much much less organized and much more prone to splintering and infighting. the thing you’re forgetting is that the democratic party is loathed by the leftists and even more left wing liberals of the US and doesn’t
represent them at all. the right wing party does a much better job pandering to its more extreme and willing to actually stand on their beliefs contingent on the far right but fails to explicitly organize them since outright defending and encouraging nazi groups is a faux pas no matter how vocally they support you