It's a strength because we finally get to interact amongst the left without having to explain how society works to every ignorant conservatwat who thinks they can conservasplain some bullshit. It's what makes it great.

"For example, in terms of attracting new users" - meaning that's the whole point of the question, so I'll address that.

Lemmy isn't a corporation and doesn't have to think like one. Market share means nothing. The goal is a high-quality app that does what its users want. If a majority of those users have a similar range of political views, that's just how it works out. There's nothing stopping ultra-conservatives from spinning up Lemmy instances if they want, blocking communities whose overall personality they don't like, and banning users they don't like. If this balkanizes the lemmy userverse, I don't see that as an issue.