I was taught that you should never complain If you can't put forward a solution.
I haven't read any solutions from the RSPCA, but there's definitely 3 good ones mentioned here already.
I wonder how they'd go if every joey was delivered to their shelters
Fortunately for them it's time and cost prohibitive.
I have been asked a couple of times if I could give the joeys to a old local woman who likes to raise them, I think she is blissful unaware of just how many of the poor little buggers I'd destroy in an outing.
Personally I keep a very sharp blade on my side and cleanly and quickly removed the head with a single stroke using the mother as a chopping board.
On the odd occasion iv taken a second shot if I see a joey pop out for a look when the roo drops.