A couple things:
1 - The feedback system was something that was added in by request only about 5 years ago. The site was almost 6 years old at that point.
2 - Admin updated it a while later so that the member leaving feedback has 24 hours to amend it once left.
3 - There is no mechanism to refute feedback. I imagine the thought is, if you're that concerned about it, you'll work something out with the person who just laft you bad feedback to make it right (so it can be amended).
But seriously, how hard is it to keep 100% feedback? I was out of work for 3 months in 2016, no negatives. I was travelling for work for 11 months, no negatives. No neutrals either. Communication is key and if you can't trade, don't accept the trade.
-- Dan --
Note: Please see my profile for more info regarding trading (section updated 3/4/2024). I have added a large portion of my inventory to the site, and currently have trading turned on (details are in my profile).