Hi Matt
Hubert is 99% right - there's no easy way to delete a component category. However, there are actually two (nasty) ways to do it. (But only if you're feeling very brave.)
Either way, make sure that there are no components in the particular category prior to doing this.
1. Use the ODE (part of the Workflow SDK) and define an appropriate deletion criteria on "pat_category".
2. Use a SQL Query tool, and simply delete the offending row in tb_pat_category.
Please note that this is not endorsed by Adobe, and misuse could cause data loss, loss of appetite, bad breath, etc.
Howard