git-obliterate retains old commits?

I tried to use git-obliterate to remove sensitive information from a commit I pushed to github. The command successfully rewrote all the commits to exclude that file, but didn't seem to delete the old commits — i.e. all my commits are now duplicated, one version that contains the file and one version that doesn't. What's the easiest way to remedy this? Going through and rebasing every other commit doesn't exactly seem like an effective strategy... any guidance would be helpful. Thanks!

Start by reproducing the report with git-obliterate on a repository containing a sensitive file, then inspect the rewritten commits and remaining references. Determine whether the old commits are still reachable after the command; done means the documented remediation reliably removes the unwanted history without requiring manual rebasing.