Globalization is all about cheap labor. With a free flow of illegals, corrupt businesses get workers who have no legal protections and who will work for below minimum wage. They win. Americans lose. This is not something that can be made into a positive for working Americans.
People do not have to be ‘illegals’ to participate in globalization. It is more about companies moving around than people illegally immigrating.
It is not just about manufacturing. It is also about companies using knowledge labor through the internet. For example many jobs can be done in India, China, Vietnam, Philippines ... and the ‘product’ (design, research, analysis, accounting, etc) is shipped over the internet to the employer.
Globalization means many people are competing globally for employment, whether they know it or not.