How do we fix/improve this culture of toxicity?
We don't because:
- it's a wider issue than 'the Internet'. Haven't you noticed how even politics in general, which was supposed to be the epitome of our democratic societies, has morphed into an hate-filled shit show at best, when it's not effing openly celebrating murders and assassinations of people we don't like?
- we're part of the issue. It's not a 'them' vs 'us'. It's us. And most of us, no matter what we believe in, are acting like morons, at best.
but Lemmy seems to have gotten worse alongside the rest of internet culture, proving me wrong.
Lemmy has not "gotten worse" in my opinion. It was worse to begin with and when I arrived a few years ago, the first thing I had to urgently learn is how to filter out what I call its 'noise': that constant (and self-celebrating) hatred for 'the other camp', the hatred for those who dare not think like 'us' (I certainly don't put myself in that group). I then moved from Lemmy to Piefed, mostly because back then at least it offered me simpler/more efficient ways to filter out that noise.
How do we fix/improve this culture of toxicity?
Like mentioned in other comments, the only way is through changing (civil) society itself. Aka through education.
As long as our respective public educative systems (I'm from France, but I know it's as shitty in the USA if not worse) are allowed to not do their job of actually educating and teaching kids some common values and principles (next to some actual knowledge and know-how), toxicity will thrive.
It thrives because it has been normalized and because those who benefit from it are being regarded as role models. But it's even worse than that: just publicly discussing this issue and its causes would expose anyone to being... punished by an angry toxic crowd of people that don't want to hear they're being toxic (or that their 'ideology' they want so hard to believe in have morphed them into assholes). That is a huge loss for any freedom respecting society, and a huge win for those benefiting from that hate/toxicity.
edit: clarifications.