From the POV of a Reddit veteran who had migrated from Digg prior to the v4 update that killed the site, it's absolutely shocking how much better the Lemmy (or at least Lemmy World) community is.
I also feel like I have a lot more freedom to speak my mind on Lemmy.
My problem with Reddit is that I have had to self-censor my comments to avoid getting them automatically purged by bots. It's like I cannot even use words/phrases like 'snowflake', 'cuck', 'incel', 'Trump', 'soy', and many others in a comment, because some fragile power mod decided to effectively shadowban those words. Context doesn't even matter.
Reddit mods are the kind of people who look up to the dystopian ideals George Orwell presented in 1984 and think that banning an entire lexicon of words is a great idea to control people.
As for why I think Lemmy is better, my hypothesis is that everyone with a moral compass left Reddit out of disgust, and what remains is a sea of toxic assholes.
That's a mindset, so it could easily migrate. The fact that Lemmy is decentralized means that instance admins can start flushing mods who decide that they're going to be dictators because their lives suck. Admins who allow toxic mods will find that users migrate to other instances.