The only way to opt out of having your contributions removed from any public topic or post is to delete the content itself. The good news here is as the author of the content, you are able to edit or remove them, if you choose to.

To view, edit, or remove any of your contributions from the Community, again go to My Profile in the top right corner, and choose Edit Profile. From here, you can see all the Posts you have authored and Comments you have made.

Should you have any issues editing or deleting your contributions, please contact community.manager@workiva.com to have the content removed.