I'm in agreement with Youkai on this subject. It is more the open public. It isn't the people that reserach their animals, purchase them from breeders or brokers. It is people that want something cool out of a storefront, that are uneducated on what they are getting in to. Impulse buyers make up the majority of the "dumpers" out there. Many stores stock these animals - small, cute, and cheap - which at the time appeal to those buyers. The rescue-prone animals are the most commonly available, cheap animals that the public pounces on. For this reason, the store I work at will not stock any of those animals, and are only available via special order. We don't stock anything that is for experienced keepers.
I don't keep a lot of rescue-prone animals, and am not considering keeping any of them in the future. Why? Because these animals do not appeal to me. I don't want to keep something I don't like that much, and it isn't fair to the animal either. It isn't an elitist attitude by any means - I don't like anything aquatic, so it's not a grudge against the commonality of RES... I have an iguana who is 20 years old who I love, but I will never get another because I don't like them... I have some normal leos which are awesome... I even recently aquired a cornsnake!
If someone likes certain types of reptiles, there is no sense in obligation to the rest of the reptiles if they do not like them. If the keeper dreads the work involved with that particular throw-away animal, or whatever, the animal is liekly to receive minimal or even insufficient care. We need to keep what we like for the sake of the animals, unfortunately we cannot protect a lot of these animals from people that do not realise what they are getting themselves in to.
On a sidenote... although irrelevant to the topic, it has been debated some and I would like to put my 2cp in
IMHO monitors are more difficult to care for than an iguana. Sure, monitors can live off mice, but they do best with a highly varied diet, which can be just as much work as an ig's diet. I think feeding veggies is much more convenient - I just pick up their food (and share mine) with them when I go grocery shopping for myself. I don't have to go out of my way at all. Also, the fact that most are terrestrial means they take up waaaay more floor space than an iguana (or any other arboreal animal). Not to mention the fact that most require several -feet- of dirt to dig around in. The setup ends up being much more extensive.