Buddy, Fattcatt's feedback shows as "Untrusted" for a reason.
Don't let yourself be derailed by people attacking you.
Given how high you fly, there is quite a few angles to get to you, and it's always easier to hurt people rather than pulling out fingers and do something constructive.
I don't want to analyze the fatty antisocial behavior further, ain't nobody got time for that, but they certainly are irritated by something you do or did, for whatever reason.
I believe if they were a bit less egocentric and agreed to let go auctioned items at not satisfactory prices for them, there wouldn't be so much drama.
In the end, they can only blame themselves because they ruined it all.
They didn't understand that it should be better to publicly apologize in Reputation, state they understood what happened and promise it won't happen again.
They still don't, since they resort to trashing people. That won't fix a thing.
Ultimately, it's up to them to decide if they want to fit in and respect the consensus or rules that is established, or don't respect it.
If they don't, well it's only them to blame, it means this place is not right for them.
Leaving feedbacks to warn other people that this user doesn't care about the set of rules that is established as a consensus is good, since different parties can't expect a "regular" trade with Fattcatt.
Now about Be Your Own Bank.
I think the project is cool.
BYOB stands for "Bring Your Own Bottle" initially, and I like how you turned that festive acronym to apply it to physical bitcoins.
We are in a such particular time and place (regarding crypto-currencies and the technology of money since the dawn of humanity as we know it).
I believe that any project today in this space is niche and should be encouraged. It has lots of potential and is much more important than what we perceive.
Sure, there will always be controversed artists but you cannot be appreciated by everybody and abide to your own sense of morality at the same time.
TL;DR : It's easy to break stuff and hurt people, not that easy to build something. Keep doing what you're doing. You are nailing it.