Maz,
One simple answer to your question.
Come down here sometime and say hello to "Sparky". He happily goes straight up and over 6 foot fences without a second thought, still catches more rats / mice / birds than you can shake a stick at.
Is still a very loving "lap cat" when he wants to be, but it never lasts long and he's back at the door stamping his one remaining rear foot asking to go out again soon enough.
Just come on down and look this full-of-life and clearly very happy-with-life cat square in the eyes and tell him that a bullet would have been kinder! Who are you trying to kid - my full of beans cat or your own personal prejudices?
I thought long and hard about what I was putting him through and I sure as hell did not do it just for me. Remember that, about six months after this surgery, he got hit by another car and broke the leg again and at that point I decided that I couldn't put him through that sort of surgery again, so we amputated instead. Do you assume that I had suddenly "fixed myself" in the interim, or is the more likely scenario that in both circumstances I was actually acting in the best interests of the cat (at both times, guided by the best vetinary advice available)?
You know that I love you as a person, but you really made a poor psycologist.
Dave