Too much focus on the company in this discussion and not enough focus on the act, IMO.
The real question is: Is it ok to blow your breath directly into a "sealed" food product? If I'm at a local farm stand, is this act just as acceptable if a high school kid does it for the same reason? Maybe. But it's still pretty odd.
If somebody at Dominick's did this (god rest his/their soul

), would that be just as acceptable? Probably not.
Most of us have purchased a goldfish from a pet store before - they "blow up" the bag with air for the fish too, but not with their mouth....because that would be completely weird. They have a little air hose connected to a pump that costs probably $4.00 total.
WF could "fancy that up" a little, maybe even pump in pure, 'organic' oxygen that has been sitting on fresh nugget-ice infused with essence of kale, and it would be quaint and clean, and germ free! Feel free to sell that idea to WF corporate office.
Of course it's completely weird and inappropriate for somebody to close a bag around their mouth and blow their humid, germ-infused breath on your groceries.