Almost all software shops are not unionized. Jobs move overseas because companies are not expected to act as beneficial actors in other countries, they know they do not have to respect basic human rights or pay a fair market value wage for labor.
The corporation freely signed a contract with the union to follow certain stipulations. There is no bullying on either side.
The breakthrough unions provide is a power balance from which your profession can advocate for setting base pay, working conditions and benefits. It provides a front against mismanagement/abuse and ensures you get the protections regulation and contracts provide. These are problems that existed in the past, exist now and will exist in the future as long as organizations of people are around.
You have a mischaracterization of unions of simply existing to force money out of companies, when their purpose has been explicitly stated many times.