That’s correct. It might be misleading because of the language, but wikis are, fundamentally, still topics to Discourse. The trust level overview notes that TL3 gives the ability to recategorize and rename topics, which means that they can, by extension, edit wiki titles. Again, wikis are just topics that have enhanced edit permissions.
If you want users to be able to edit wiki titles, your best bet is for them to either gain or reach TL3. They can always use the flag system or PM a moderator to change a topic too.
Somewhat confusingly in the UI, a wiki’s title appears editable (in the composer) even if the user can’t change the title. That’s probably non-ideal.