Is me writing a blog post about how much I personally like hamburgers a business? Because that can be interpreted as having business intent in Germany. As soon as I drop the name of a fast food restaurant, it can be interpreted as advertisement that I got paid for. Yes I could easily prove that this isn't the case if asked, but thats work.

Not so. German courts actually take a look at the site and apply common sense judgement. If it's obviously a personal blog, nobody is going to successfully litigate against you. There's a lot of FUD involved in these discussions.