Walter says this hurtful line to his mother because he was upset about how she used the inheritance money for her dream of a house. Walter had been feeling frustrated and constrained by all the limitations on him. He wanted to use the money to invest in a liquor store. When he found out how his mom used the money, he felt like he had to give up on that dream, and he saw this as her fault.
Because of his deep anger, the words Walter uses to express his feelings are calculated and hurtful. Mama did not buy the house with selfish intentions, but rather to fulfil her dream of having a comfortable home for her family. She loves Walter and is not the type of person who would deliberately hurt her children. Deep down Walter knows this, but at this moment he wants her to understand how hurt he is, so he chose words that painted her as a bad mother to hurt her feelings. For instance, when he says, "You run our lives like you want to," he makes Mama seem self-centered. And the use of the phrase “butchered up” brings to mind an image of intentional violence. This image describes how hurt Walter feels inside, but it also seems to be intended to make his mother feel really bad about what she did.