You're right there are areas in the US where you can work as an ASN nurse and not have to do any more with it. However Boston is not one of those areas. If you look at the New Grad programs for any of the top hospitals (BI/Lahey, MGH/Partners, Tufts) they all want BSN or Senior Capstone students. That is not to say that you can't apply for a position outside of the New Grad program but it won't be as easy.

Looking at the link you provided those jobs look to the in the Pacific Northwest, Kentucky/Tennessee, and Texas all of which got decimated by Covid due to various reasons.

The nurses that work in the states and do not have to retake the nursing exam are probably able to work because of reciprocity with the Nursing Compact. It is a nursing license that is applicable in different states, MA is not currently one of those states.