It doesn't matter that he didn't actually write it. The lip-moving readers of the New York Post believe he did, and so probably did this racist moron cartoonist. And the right is tagging Obama with this stimulus bill in any case. It's widely regarded as his.
First, this wasn't a major newspaper, this was the New York Post, which qualifies as "major" only by circulation and as a newspaper only by stretching the definition considerably. As a comedian in NYC said in my presence 20 years ago, "New York only has two newspapers, unless you count the Post, and why should you?" And second, right-wing loonies will do anything. If you think Faux News' ("We distort. You deride.") coverage of Obama's candidacy wasn't racist, you probably won't accept anything short of an actual lynching as being so.
And now you're asserting that you have telepathy for the mind (such as it is) of the cartoonist. You don't know his intention. Besides, racism can be unconscious. Even if he WASN'T thinking "I will now draw a racist cartoon," his racial prejudice could be operating. And people who don't think they're being racist often have attitudes that any reasonable person would identify as such.