No one in saying pilots should, work for minimum wage, but 28k is not a terrible staring salary, admittedly less when trying repayments are taken into account.
The reality is that an airline like RE does not want long-term career pilots. Their payscale (or alleged lack thereof) makes that clear.
What RE are offering is the ability to come home every night, being based near to where your family/life are without uprooting. People make choices. Not everyone is motivated by a massive bank balance, so I don't think it's fair to say that pilots at RE are necessailry under/overpaid. Many of the crews I have met on RE flights are with Arann for exactly that reason. A 100k salary at BA ain't much good if you spend more time miserable in a Travel Inn in Crawley than at home with your family.