Wow, i saw that add on kingsnake and i know who you are talking about.. Not personally, but he has delt with my 2 friends that are breeders.. I was surprised to see that add as well. As far as my friends (the breeders) are concerned, it shouldnt be allowed to be that way... They say yes its sometimes a hard decision but when you really care about the welfare of the animal and the entire genus as a whole, you dont let the seriously deformed ones out in public, where they may fall into the hands of someone who will breed it and pass on genetic problems..
I personally would find it hard to put down any animal but if its necessary i will. I had to put down an older painted turtle i had due to a blockage she had and she was suffering.. As for spiders.. I cant comment on that seeing as im getting a Bee.. But i will not be putting it to another spider or spider morph. I simply would not do that and risk creating snakes with serious problems.. Just my opinion..