Think about things from the point of view of someone who has never used Reddit or the fediverse, but you've heard about them both from recent news articles and want to see what they are about.
Reddit:- You Google Reddit and your first result is Reddit.com. You click the link and are presented with the front page. You from scroll from a few hours and end up signing up and staying.
Lemmy:- You Google Lemmy and your first result is a wiki article for Lemmy Kilmister... Your second result might be join-lemmy.org, which you're smart enough to realise it's probably more likely what the news is about.
You click join-lemmy.org and are presented with a page of information about the fediverse, links to set up a server and pictures of code...
There is very little chance you're going to investigate further.
If we want the fediverse to replace Reddit then either
A) Lemmy needs to improve its initial impression and Search engine optimization
B) We should be promoting a different platform with a better initial first impression.
I'd recommend kbin personally as it gives the same sort of experience as Reddit from the initial interaction.
You're gonna need to be a bit more specific than that, because "defends" often does a lot of heavy lifting when it comes to issues like that being discussed from a leftist perspective. Did they outright say North Korea is perfect or there was no human rights issues with the treatment of the Uighur people in China? Or did they say the situation in Korea is more complicated than is presented by the west because we've embargoed them for more than half a century at this point and point out how the Uighur genocides are not that different from what happens in ICE camps in the US to this day?
Bad things happen all over the world, and I don't think China or DPRK are perfect by any measure of the word, but presenting them as the axis of evil and ourselves as the good guys is just silly. It's not that they're good, it's that we're cartoonishly evil too.