The arguments against this seem to be:-
1. I don't want to continue working so why should you - answer - it should be personal choice not dictating it.
2. You are blocking commands - well if I had the choice to continue working I would have gone 50% a year ago instead of staying full time to top up my retirement funds so ATM I am blocking commands more than if I could continue working, I suspect many others would do the same then work on maybe another couple of years so 6 years at 50% instead of 4 full time, with others doing this it would create openings rather than block them.
3. If we can work past 65 employers will force us to keep going when we do not want to - ???? I do not understand how they will do this, if you can afford to retire at 45 then you hand your notice in and do so, nothing is FORCING you to keep working.
4. You are being greedy working on - surprise surprise, some people actually enjoy the job and do not want to pack it in, plus it keeps your brain active, personally I enjoy it but like many of my age would just like to do it a little less (see point 2!). Even if they are doing it for the money it should still be THEIR choice, after all, the money is what most people go to work for!
there seem to be very few people arguing against this on sensible grounds just people that do not want to do it themselves and so think others should not, we should ALL have the choice, if you don't want to work on that is fine but don't block those that do want to, and many younger pilots who are objecting now may well be glad of this when they are approaching retirement themselves and state retirement age has gone up more or is paying less!