IAM roles and CloudFront are what we call “Advanced Clouds and Discourses”. The majority of installers aren’t going to be able to figure it out. It’s a reasonable setup, but out-of-scope for the intended purpose of that rake task. So I’d call this a feature request, not a bug.
If the bucket is supposed to be public, then changing this will copy over a bunch of private objects and the posts will show broken links.