It has been over 10 years since I owned an iguana and was not aware of the change in acceptability of a small amount of animal protein in their diet. And I'll bet the owner of the iguana in question isn't aware of it either.
As for the "cruelty" of the act...I'll stand by my original statement. I prefer to feed dead prey, but will feed live if I have to. Animals killing and eating other animals occurs every day. It is a part of nature. I may take "offense" to the feeding of a kitten to a pittbull ONLY because my society as a whole is SUPPOSED to be offended at it. If the feline was not kept as a pet in our society, but was instead kept as a food source, I would not be offended. It would then be the same as feeding a sirloin steak to a pittbull. Now in India...THAT would be offensive as the cow is sacred.
"To each his own.", said the farmer as he kissed the pig.