Revert 42231 bug mi should compare
- [ ] closes #xxxx
- [ ] tests added / passed
- [ ] Ensure all linting tests pass, see [here](https://pandas.pydata.org/pandas-docs/dev/development/contributing.html#code-standards) for how to run them
- [ ] whatsnew entry

Note that this PR is not onto master, but from my fork of the "revert-..." branch onto pandas-dev form of the same branch.  I couldn't find any other way to merge master on that branch. Not sure what happened here, but this is a duplicate of #42575, closing.