Publix was named one of Fortune's 100 Best Companies to Work For in 2012.....
As far as the bag thing, every company wants to save money. And many of them do it in a PR friendly way by using a green initiative. (Universal Orlando for one) I doubt company policy is to cram as many things in a bag as possible, crushing everything. But I'm sure you should try and fit as many things in a bag as possible without crushing everything. This feels like either one very bad manager or people taking the instruction to the extreme.
And as far as having baggers that do everything get paid the same as baggers who just bag, if your in the same job title then yea your going to get paid the same thing. Again this might come from a specific stores bad managment?
Overall you don't get listed on a list like best 100 companies to work for if your employees all hate it there. In fact everyone I know who works at publix loves it.