Mundungus Fletcher suffered, and more can only blame him for his love of death. As a member of the Order of the Phoenix, how could Mundungus not know how deep the hatred between the Order of the Phoenix and the Death Eaters was. After his identity as a member of the Order of the Phoenix was exposed by Snape, he didn't choose to hide. Instead, he swaggered into other people's homes to do business without money. It's like playing disco in a latrine - looking for shit.