I think Carl Worth has already done a great job of explaining the situation... as he noted, I did give credit to Josh for the card idea long ago, and I really didn't think further attribution was necessary. People suggest card ideas to us all the time, and many of the same ideas get suggested over and over again, and it really isn't practical or even reasonable for us to try to credit everyone who makes any sort of suggestion that we end up using in some way. We try to be inclusive when listing names in the credits for full-fledged publications, but even then it's just not possible to acknowledge every suggestion made by all our random playtesters. As Carl noted, it wouldn't make sense for us to be putting specific people's names on every card first thought of by someone other than me.
So again, please pass along to Josh that we're sorry he felt misused but that he's free to tell everyone he knows that he's the person who first thought of that card -- and that he is indeed credited with doing so on our website.
-- Andy Looney