って and は mark topics, not grammatical subjects. They can replace both the subject marker が and the direct object marker を.
(Another way to think about it is that you can omit subjects and objects if they’re clear from context - 聞きたくない by itself is a complete statement. And then you can provide that context with a topic and make the statement into a comment on that topic. There is no explicit grammatical connection anymore, so the grammatical function of the part you omitted is not so important.)
NB: Verbs in the たい form work a lot like adjectives and can take a subject marked with が instead of a direct object marked with を. In most cases either can be used with no real difference in meaning.