The stats that I heard after the election were that Harris got more votes in the 6ish key swing states than Biden did.

If that's true, and your claim is also true, it means she got a lot less in safe states where it frankly doesn't matter. Maybe sexists decided not to vote for a woman, especially since they already knew who would win their state. Maybe it was genuinely about feeling Dems were too far right to be worth voting for. But it doesn't actually matter because it's a safe seat. Where it actually mattered, these people held their nose and voted for the harm reduction option.