It's not an account, you're signing messages using your private key, probably through a browser extension like Alby.

When you read your timeline, you're viewing public data that anybody can see.  This doesn't require any special privileges, I could do it without your private key.

If you set your Alby extension to confirm every time, then it won't sign messages without your confirmation. If you want to see another timeline, then you can switch to it by adding the users public key to a signing device.

I appreciate it's a different mind set, but unless you post something or pay somebody, you're not using an account at all.

But yes, a "Forget this feed", option would be useful 😂