The amounts concerned are generally the ‘welfare’ component of the Social Security program.
Social Security redistributes money from high annual contributors to lesser annual income contributors.
Many but not all government retirees should be allowed that ‘welfare’ component.
That is a general belief. But, in reality, you are reimbursed according to your primary insurance amount (PIA) which is based on exactly what you paid into SS. In my wife's case, she paid into both social security and teachers retirement at the same time. As such, she should receive full pensions from both, and not penalized because she also paid into a secondary system.