Well, as HRE or France, you're going to get into plenty of wars. Both factions start with a large number of provinces and a large number of bordering Rebels, so you can get ~15 provinces relatively quickly. Once you get to around that level, the AI sees you as a global superpower, and random factions will just try to kill you. This is compounded by since the allies of nations your at war with will trend to hatred, making them more likely to go to war with you in the near future. The only way to really avoid this would be to expand much slower. Besides that there are a number of ways to mitigate the actions (Be nice to the Pope, only really attack one faction at a time since the AI can't conduct a true offensive, dish out cash to other nations, etc.), but they won't truly solve your problem.