HPV, and why does inoculate only have one N?

More states than not are dealing with some flare-up or another over the HPV vaccine. Here in Texas, where Gov. Rick Perry's executive order made the state the first to mandate the shots, the issue still makes daily news. And there's been plenty of potential for error:

First, inoculate is spelled with one N, one C; it's not innoculate. Why doesn't it have two N's like innovate or innocuous? They get their second N's from a different part of the root. Inoculate is in+oculus for inoculare. The other two words add the second N from their root: Innovate is in+novus for innovare. Innocuous is in+nocuus for innocuus. Hence the two N's.

Some other tips:
The vaccine is Gardasil, not Gardasill.
The pharmaceutical company that makes it is Merck, not Merk.
HPV stands for human papillomavirus (two words), not human papilloma virus (three words.)