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.
As my feed is populated by a lot of German threads it is worth to note that moderate depends a lot on the country you are from. Bernie Sanders would probably be considered part of the moderate left in most of Europe while he is considered to be far left in the USA.
It also depends about what specific topic we are talking about.
In many places in Europe, being a social democrat when it comes to economy (like Bernie) might be considered pretty moderate. But then certain attitudes about non-binary pronouns or supporting special considerations for specific groups of people, are seen closer to "far left".
You don't see the amount of virtue signaling in Europe that you see in USA media productions, for example.