Looking at the differences between multi-server fediverse relations and multi-server Bluesky relations ought to make it easier to see why Bluesky couldn't just lift Mastdon's moderation solutions wholesale. And it opens up a bundle of questions about how federation and moderation work on the Bluesky network that probably won't be clear outside of the company until the beta ends and third parties start federating their own servers into the network.
Some questions about how Bluesky will work once there are multiple servers:
• Will servers be able to defederate from one another? (Presumably yes.)
• Would that block public posts, or just direct posts? (Maybe the latter.)
• Will servers be able to defederate from indexers? (I'd guess no.)
• Are blocks processed at the host or index level? (Hard to say.)
• Will users be able to filter at the host level (e.g. by keyword), or only the algorithm level? (Looks like the latter right now.)