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.
It gets weird when we talk about this stuff on only one axis (left-right) rather than two (left-right/libertarian-authoritarian, though that's still a simplification). Specifically, I'm an anarchist, which means I'm part of the "far left". Anarchists, along with "ultra"-communists, are seen as being to the left of Lenin/Stalin-style communists. Saying that the problem with the lemmy devs is that they're "far left" implies that people like me are the same as tankies, and we kind of resent that.