Currently Ideas creators can go and edit their initial idea, but they can't edit any comments they've left. Any Aha! user with Owner permissions on the portal can edit a requestors comments.
Allowing users to edit or remove their comments will be very beneficial for promoting a healthy culture of commenting on ideas.
A few use cases of why a user might want to edit/delete their own comment:
Commenter notices a typo
Commenter adds a comment to ask a question, then realises what the answer is and is embarrassed by their question.
Commenter has an emotional response and rethinks things later
Commenter wants to change how they word a question for the sake of clarity.
Commenter accidentally posts sensitive information.
In all of these situations, a commenter will likely want to expediently change their comment. Having to figure out that not only can they not do it themselves, but who they have to contact, how to contact them, and then wait for the "Owner" user to edit it on their behalf is a waste of time and a poor user experience.
It also wastes the time and resources of the Owner who has to make the change.
This could easily be solved the same way that people who create ideas are allowed to edit it.