Remember-Zara has a policy to never pay for advertisements.
This is a PR stunt, and not their first one and it worked, obviously.
Moreover, it combines getting a free whack of publicity along with showing their clear contempt for Jews at the same time.
Perhaps a drop in the bucket, but I'll never buy anything from Zara ever again.
With a chain this large and with such tight control on the brand, I don't even think that once could be a "mistake".