Stupid people wanted to claim that Harris was “the same as” Trump.
What we have here are voters who thought Trump would be better than Harris, not the same. I can understand, even if it's technically wrong, when people feel that genocide is genocide. And they see what is happening there as an extension to them (which any psychotherapist who's dealt with someone of an ethnic group which is in war can attest to).
Most of these people are in their own echo chambers
Although this is most probably a factor, I believe this to be too simple an explanation. So about the media landscape: Yes. Especially the so-called 'new media' is seldomly truly independent but often biased in that they peddle this false narrative that Trump is a peace candidate. Also notable is that 'alternative media' is largely seen as independent from billionaires and power, while legacy media is an arm of the establishment. So the narrative of 'us vs. them' works even better and since the biggest names lean more right or are outright Republican propaganda channels, this could translate into more people who already resent the status quo falling for them. And thanks to the engagement-optimizing algorithms they fall into these echo-chambers. Sidenote: I'm not de-legitimizing alternative outlets, but want to stress the importance of scrutinizing how they finance themselves. We just had a case of one right-wing propaganda channel being exposed as being financed by a Russian oligarch for years. (I forgot the name)
One could also point to the rhetoric and behavior of the two candidates towards the pro-Palestinian population in the last few weeks and months before the election. One side didn't let Palestinian voices be heard and even actively and preemptively removed an elected Democrat from one of their own events, because he happened to be Palestinian American. Outside the DNC the protestors were met with disdain and ridicule by DNC delegates. And the other side came to speak lie to them about what he's gonna do and that he takes them seriously. People are gonna see this.
Or generally when Harris said that she wanted the 'most lethal military in the world', while the other side talked about ending wars 'within the first 24 hours'. Outrageous but a stark contrast.
Or the simple sentiment that with the Dems in power genocide is happening, so I'll roll the dice. The same anti-establishment sentiment that led to Trump in 2016 in the first place (economic in nature in 2016).
Talking about anti-establishment sentiment: I know of only one exception to this. But after COVID, there's only one incumbent party in the democratic world, that came out of elections still in power. And that's Mexico. If you know any others, please feel free to enlighten me.
The list is not extensive by any means and is just me spit-balling. If we want to understand what happened the answers are going to be much more complex.