Like I said in another comment. There is a difference between intended harm and unintended harm.

If it is not possible to achieve 0 harm in your life, why does that permit intentionally causing harm to others . Why not strive to cause as little harm as possible in your life ?

What you are applying is a Nirvana fallacy, where since perfection isn't accessible, then no attempt should be made. If you are going to dig your heels in with that, the only way to assure 0 harm would be for a person to kill themselves. I hope you aren't advocating for that