Yglesias, assume your readers read the report

Federal spending cuts deserve the most attention. They are the most likely of these issues to occur, and could have the largest magnitude. The assumption we incorporated into our recently revised budget estimates—discretionary spending cuts of $25bn and $50bn below the CBO baseline for FY2011 and FY2012 respectively—would shave nearly one percentage point off of the annualized rate of real GDP growth in Q2, but would fade quickly with a negligible effect on growth by year-end.

This is what the Gololdman Sachs report said, not what you implied.

Alec Phillips, the author of the report is simply calculating the adjustment cost as money is shifted out of the government sector and into the private sector.  The entire gist of the report if one clicks into the link is that it will be business as usual because Republicans love big government just as much as Democrats.  Goldman's entire bonus system is built on the continuing idea that Washington DC will somehow get California, Illinois and New York to cover the debt service fees.

It is the Internet, Yglesias readers may not follow through, but plenty of others will follow the links.