Just reading the addressees of the ones who have objected, it is clear that they are local. If I was a local business I would be concerned that so many very local people objected to my presence, even if they are not potential customers. That is because they probably have the potential to influence others

Those 500 are not the extent of the opposition, they are the ones who felt strongly enough to do something about it.

Many many more won't be aware of Dominos until they open the shop. A leafleting campaign to point out that people have a choice over who delivers their pizza in the event that Dominos does get change of use planning permission will undoubtedly harm Dominos.