Gawd, Six Sigma was an ever-present factor in all our work when I was at IBM in the late 80's to early 90's. I have complete respect for Deming, but when anything becomes "religion" it gets damaged or mis-used a lot, as you say.
In our software group, we were constantly battling with management that wanted to start to look at software development as a factory-like process, and to apply factory QA processes.