I'll try to explain in the simplest terms that I can. Trump might have won if it weren't for the pandemic; voters have been routinely re-electing Presidents since 1996. I can see how his supporters might be frustrated and disappointed by the outcome. Personally, I've been frustrated and disappointed by election outcomes my whole life. But it's important to understand why these things happen.
1. There was a recession economy in 2020. Whether it is right or wrong, voters often place blame for a poor economy on the President. This sort of thing caused Herbert Hoover to lose re-election in 1932 and Bush 41 to lose in 1992. To be sure, the recession was caused by the pandemic.
2. Trump's response to the pandemic was bad. He had federal agents seize medical supplies from hospitals. He visited patients in hospitals without wearing a mask. He kept holding public rallies in spite of the danger, and ended up getting sick himself. That showed poor judgement.
3. There are more liberal and progressive voters in the US than there are conservative voters. While a typical conservative is more reliable and more likely to show up for every election, higher turnout means more liberal voters are at the polls than conservatives. Higher turnout helps Democrats and hurts Republicans. There was record turnout in 2020 due to emotional charged events and state election officials working hard to allow voters to participate safely.
