Why does AAMC advocate more residency slots when it hurts physicians?

Got an email earlier from the AAMC saying “Specifically, AAMC Action advocates on behalf of increased support for: New Medicare-supported graduate medical education (GME) positions to improve patient access to care by training more physicians to address primary care and specialty shortages in high-need areas, such as mental and behavioral health.” Have they looked at radonc and EM? Why would they advocate for this?
Source: Student Doctor Network - Category: Universities & Medical Training Authors: Tags: Medical Students (MD) Source Type: forums