Gun,
You can do anything you want with the code because I released it for free, but don't say to your customers that you have developed from zero like @Sweeet said. And cite the developer when you copy something from someone that spent nights developing this thing. This is how open-source works.
Why are you trying to crash something he has going, you obviously don't want any money from it so why are you trying to get rid of his customers? He never specifically said he created it from zero or he did it with out help. If all you want is attention why didn't you ask Gunthar personally rather than attacking him.
Everyone knows that you can get a product like this for free, but we don't buy it just for the product, when you buy from Gunthar you get debugging, personal support, advice, and all the other attributes. Everyone knows anything could be sold for less but you don't buy it for its price you buy it for what it comes with. Well unless your trying to save money.