This country has lost its collective mind.
I think that due to media (us vs. them) echo chambers and the popularity of nihilism and pessimism on social media, people are just predisposed to hate whoever is in power.
Remember, Trump had very middling approval ratings despite presiding over a period of prosperity and stability (pre-COVID). Same thing happened in Obama's second term.
It's only after they leave office that voters soften and look at their presidencies with rose colored glasses.
Right now, Biden is bearing the brunt, and because of his under-the-radar leadership style, his age, and the fact that he was more of a consensus candidate in 2020 with no rock-solid base, he's an even easier punching bag.
If Biden loses and fades from public view, people will be able to look at his record more fairly. He's gotten a lot done.
