> US-centric political moderation on top.
This is something you opt-in to. Two concepts, labels and moderation policy.
You subscribe to "labelers" which will apply labels to posts. You can subscribe to many labelers. Some labelers will be generic or some will be focused on a certain idea/niche. You might have a labeler focusing on nsfw content or another for human vs ai content. Or one who just tags spiders. Labels can be anything, and are stand alone data objects in the atproto ecosystem.
Your moderation policy is up to you, on how to handle those above labels. You can decide to allow, warn, or block for each label applied by your labelers. Warn shows a content warning you must click through first to see.
Bsky does have a default labeler and moderation settings when you sign up, which you might be experiencing.
