You're right, they made up reasons to go fight other nations, or fought wistfully in the name of religion, or because so and so insulted your cousin, and didn't marry your sister the Queen of the other nation.
But they didn't fight suicides either. I could be wrong but I am pretty sure random little nations didn't go !@#$ with the HRE. They might have fought a plenty but they weren't idiots about it, AFAIK.