Am I the only one to be blamed for forwarding the money in such a stupid way?
Well, you did send bitcoins without any guarantee that he would finish the work/refund you incase something goes wrong, which was a stupid move IMHO
or he is to be blamed too, for giving bitcoin such a bad reputation, for being a heaven for scammers?
If you deal around the forum and follow the guidelines etc, you have 0.01% chance of being scammed, so , no he isn't to be blamed for bad reputation of bitcoin, its like saying dollar should be banned because its used in unethical business, or saying guns should be banned because many people might misuse it. Bitcoin is just a tool(currency) , what you do with it depends on you.