You would think they would test these patches better before releasing them
Read the article.
As the number of reports grew, Microsoft first stopped automatically serving the MS10-015 update, then confirmed that a rootkit caused the crashes. Only PCs that had been previously infected with the Alureon rootkit were incapacitated, Microsoft's investigation found.
The problem was caused by an infection already on their computer, NOT by a Windows update error.
They do, but you can’t test everything. I’ve been in QA for 15 years and “test on virus infected machine” has never appeared in any of my test plans.