How's that safety argument doing when they continue to pass the same FAA medical you do, and continue to pass checking events like you do, and continue to do the job like you do, and the only difference is the calendar went past a date? Many would argue that keeping such high level experience in the seat is improving safety. They could also correctly add that it serves the nation by reducing the number of cancellations nationally. If they can leave and continue flying 135 jets then why not just stay where they are and alleviate some of the stress on the system.

In reality it harms nobody. The ones screaming "get out of my seat" get to work the extra two years at the end if they choose also. It's not like anybody is saying we're going to work two extra years, but you can't. So even the monetary argument is false. It boils down to the "I want it now" vs the "I want to stay." I'd say the "I want to stay" crowd have the age discrimination law on their side.
The question then becomes, will they make that same argument to push for age 70? There does have to be some cut off, but does it need to be performance driven, or just arbitrarily age driven? Should we require 3 medicals and 2 check rides per year from over 65 pilots? Should the over 65 pilot medical be more involved, to include hearing, and some stamina testing off a tread mill or bicycle? How about cognitive testing for over 65? Then the question becomes why make their medical harder? isn't the basic one good enough? if it's good enough to let you fly, why not him?

Yep, it's a complicated issue for sure. I tend to come down on the let them fly side, primarily because they can still go fly 135 carrying passengers for hire. If they can't carry passengers for 121 after age 65 then they shouldn't do it under 135 either... likewise, if they can fly after age 65 carrying passengers for hire under 135, then they should be able to do so under 121 too. I think that point, combined with the age discrimination aspect is going to give the age 67 folks the win. That and a whole lot of money from managements into re-election PAC's.