This is incorrect. You don’t have to host your own tangled appvew to log into tangled without having your atproto account on Bluesky’s PDSes.

You CAN host your own Tangled AppView. You CAN host your own knot. You DO NOT have to in order to self host your own PDS. Each of these layers are decentralized from the other.

what do you think tangled is if not an alternative appview? Tangled moderation isn't affected by bluesky moderation at all unless your account is hosted by them and you do something highly illegal like posting CSAM (PDS moderation is mainly about legal-to-serve stuff). you don't need to use bluesky or have your account hosted on bluesky to use tangled.

fwiw tangled itself is also an appview and they are gradually working on rebuilding it around their new XRPC oriented appview called bobbin.

The appeal of bobbin is it's fully stateless and pretty lightweight. IIRC you can run all the infra to run a proper tangled appview (including bobbin) all on your average lower middle end general purpose cloud instance.