No, it's not their responsibility. Because they're preaching to the choir, just like Umair is. People listen to Bannon for the same reason they read Umair Haque: confirmation bias. We think they're bad and we think we're justified. We know they think we're bad, but we think they aren't.
Thing is, people vote for Trump for the same reason people vote for AOC: they have issues and fears they think that politician can address.
But on the left nobody dares to acknowledge the fears and concerns of Trump's base (and I don't mean the likes of QAnon).
And of course there's the overarching hypocrisy of the Democratic establishment. Everybody picks on electoral college system and anti-democratic, voter suppression in Florida, gerrymandering and so on ... when done by the GOP. But nobody said anything when gerrymandering helped the House from GOP to Dem (and, of course, back and forth) or the electoral college confirmed Obama.
Biden is going to squeeze a win, most likely, but he would do so with aid from disgruntled GOP dissenters and by no means through any merit of what he stands for. His only merit is that he's not Trump and that won't be enough to get reelected. After Biden, GOP returns unless something meaningful changes.