Yes but today it is shops selling kosher food, and tomorrow it is public spaces like squares. I assure you that a Jew is allowed to enter a building with a Christmas tree. There is no reason for the shomer not to enter. The halacha allows one to be lenient on a case like this. The question is whether the Rabbinate will choose to be. This is not really about the kashrut of the establishment, it is about a closed-minded approach to Judaism and to the outside world, because the Rabbinate is an ultra-Orthodox institution at present. This is about their value system, not Jewish law.
Egypt says verdict in Al-Jazeera case expected Saturday (AP)
from the article: Israeli rabbis warn: Yule be in trouble if you put up Christmas trees