People see things differently and if you saw it that way, it's up to you as to how you tell and teach your children what's right and that goes for other parents out there as well. Personally, I see nothing wrong in those commercials because they have not "crossed the line".
Take note that the aim of advertisements is to advertise products thus right arithmetic and "generosity" is not really a big deal to them. Advertisements are not for educational purposes. It's about being creative and crafty on how to make a product more appealing to the people.