The earliest exoduses were socialist political communities banned from reddit (particularly /r/chapotraphouse who formed Hexbear, and /r/GenZedong who landed in Lemmygrad). Then, the most recent exodus is related to censorship related to Luigi Mangione, a US political issue, coinciding with a strong sudden re-emergence of global anti-American [government] sentiment due to diplomatic catastrophes with a range of former allies.
In fact, the founders cite reddit’s corporate nature and its pro-US-imperialist, racist stances as their motivation to create Lemmy: https://join-lemmy.org/docs/users/07-history-of-lemmy.html
So I’m not surprised at all that the default feed is covered in political topics, it’s always been a strong topic here and it’s just gotten stronger. But there’s probably enough activity now that one can filter it out and still have enough action to keep it fun.
Hey OP, I just want to say from experience the reddit bashing usually dies down a bit after a quick spike of reddit refugees like we’re seeing now.