I have some smelly hair conditioner that I want to keep.
What is your rationalization for wanting to keep such hair conditioner?
There's no particular reason, it's just a habit I got from my parents.
It's good to use a product up if you already spent money on it. However, if you feel like the product is harmful or off putting, it may be best to just replace it. You shouldn't force yourself to suffer over saving a few dollars.
You are being unreasonable
Hair conditioner shouldn't have a smelly odor and if you can smell it then that means other can, too. It isn't kind to expose others to such things and the conditioner should be thrown away.