No – @DbLookup works fine on the web if the formula is written correctly and the user (anonymous or logged in) has access to the database, view, and at least one document with the key specified in the lookup.
Bill’s response to your question in that thread was not sufficiently clear.
It is not true that @DbLookup will only work in a web application if the user is logged in.
What makes a difference is that the user must have access to the view and document they are looking up.
In your case, anonymous users did not have access to your view. You could have fixed the problem by changing the database ACL so that users who are not logged in can read the view. Forcing the user to login is not the only way – and in fact, forcing the user to login doesn’t even solve the problem in all cases – the ID they use still has to have access to the database!