One can't read minds and distinguish between pure political calculations and ideology, though I tend to think they overlap frequently,
but apparently the political risk of "the wrong people (aside from rich assholes) getting help and a ballooning federal payroll" was seen as a bigger deal than the political risk of "massive long term unemployment." I'm sure it's in part because they downplayed the risk of the latter, but...it's, uh, May 2011? The January '09 projection argued that if the stimulus passed, then unemployment would be about 6.8% now. Without it, about 8%. It's 9% now.