It's a software difference. Kbin is just made to be both reddit and Twitter. Lemmy is only made to be reddit. Basically.
Kine currently has problems with federation because of their cloudflare anti spam.
Under magazines you should get reddit like stuff and Twitter stuff under.. Whatever the other is called. You might get content from both under the comments sections, but I thought that was only reddit type content comments.
Lemmy doesn't federated with mastodon type servers.
Kbin is the one you need if you want both reddit style fediverse and Twitter style fediverse. Lemmy only does link aggregation/reddit.
Lemmy should get kbin content but I'm not sure it federates it because kbin allows NSFW and lemmy... Does not for the most part.
Are you comparing kbin to all of the lemmy fediverse?
Because kbin is part of the fediverse and has as far as I understand been bigger then the biggest lemmy instances for a while by a good margin?
I suspect both the tankie, extreme right and left wing content is being suppressed by the slew of new content being posted now. And that shit not getting the votes it needs to be seen anymore.