We may be on a slippery slope, but we're not quickly approaching one. Editors have fixed titles from day 1.
I think the best plan is just to make it policy that submission titles have a different status from comments. They have to, because all the users have to share the same title for each link.
Probably the best solution is to have a "posted by" (editor name) and a "submitted by" (user name) like Slashdot. Alternatively, an "edited by" tag added to anything changed after submission.
He may have meant that different users should give a specific submission the same title, one without spelling mistakes and bias. So if a user titles a submission with spelling mistakes or bias then it would be reasonable to edit the title to the correct form.
I think the best plan is just to make it policy that submission titles have a different status from comments. They have to, because all the users have to share the same title for each link.