This is based on my time working in Germany 20+ years ago. The conversations were with people in the office, not beer fans. There is no clear answer to this,
Beers not brewed by the Rheinheitsgebot are viewed with suspect. Sugars are not good for beer. Malted barley must be used, and so on.
There are many Irish bars in Germany that sell Guinness. So that is accepted.
Belgian beer uses sugar, fruit, Brett, and bacteria (in sour beers). I was told that stuff is not fit for human consumption.