The dude is bored, no one wants to talk to him, no one wants to hear him talk, he's a national pariah, and he's got nothing constructive to do. Art is inoffensive enough, especially since it doesn't start unnecessary wars and cause the death of hundreds of thousands of innocent people. And the dude just started painting, so we can't expect technical mastery. There's no need to mock his lack of skill.
That said, we can mock this:
Greatest Living President is Also Fantastic PainterWho knew that Bush boosters are still a people that exist? W is as good a painter as he was a president. That's not a compliment. But in his defense, he never intended those naked self-portraits to become public.
[...] The paintings demonstrate a command of line and color that is rarely seen in the modern-day “art” world. Former President George W. Bush appears to be influenced by such painters as Edgar Degas and Édouard Manet. The portraits also clearly capture the personality of their subject.
They were for his sister's eyes only.