Nichiyobi No Sanpomichi Debate

This problem appeared in the newspaper about a month ago, but I overlooked the article. Just recently I saw the article on the net. The headline is 'Change to ethics textbook has bakeries up in arms.' The phrase 'up in arms' means very angry.
This ethics textbook for elementary school first-graders was changed by publisher after the education ministry said it didn't properly teach 'respect for tradition and culture.' So it means that the bakery got angry for this result. Why is it?
In the textbook, an essay called "Nichiyobi no Sanpomichi" ("Sunday Promenade" in English) is at the center of the controversy.
The tale depicts a boy strolling through unfamiliar paths of his hometown with his grandfather, making fascinating discoveries along the