They were very respectful in their communications, gave a full no questions asked refund, and helped you keep your pledge.

You pledged not to buy from them and (I suppose) mistakenly did so, unaware they were on the 'list'. Had you bought from them and then they came here and publicly disclosed you had violated your pledge, you would really be p*ssed. Right?

I would not knowingly buy from them either (I have taken the pledge too) but could mistakenly buy as well. It costs them $ale$ to help you maintain your pledge. -That part is honorable-

-I agree not to do business with them too-