I think the very opposite is true, especially of German Shepherds. GSDs are extremely intelligent, as anyone familiar with the breed will attest to. They do best when they have a challenge and when they are learning new things. Having distinct boundaries and rules will help them to feel more comfortable and teaches them their place in the family.
If you can channel the innate protective instincts of a German Shepherd into disciplined, purposeful protection, you will gain an ally that will see your family through dangerous times, and give your companion the knowledge he needs to know when to protect and when to stand by.
Not training your dog to use the abilities he has is like leaving a novice with a loaded gun and expecting them to be safe. Help your German Shepherd understand his abilities and his limits and he will be more likely to behave as you want him to. German Shepherds who have a purpose are much more satisfied, too.