I don't think it's fair to put the blame on the breeders. The breeders I personally know go to extreme lenghts to ensure all their animals go to good homes and with people who know how to care for their guinea pigs. Besides, people can think for themselves right? Just who in the right mind wouldn't look up some information before buying a pet? That's the first thing an owner should do.
I do not mean to argue but, Lots of people in their right mind mosey on down to Petco or Petsmart or Petland Discounts or whatever chain is rampant in your area, and buy guinea pigs. Not knowing a single thing about them. They buy them on impulse or for thier children because "they look so cute" or "why the heck not, theyre small?". Sometimes some of theses people google "guinea pigs" a few days after they bought it and a few of them end up here on this forum. There are countless post of "Just bought a guinea pig, didnt realize the work involved!", or "Guinea pig from petco, I don't know where to start! Got the Petco Starter Kit" And those are just the few who make it here. I can't even begin to image all of the lonely guinea pigs living in their small cages with no hay or veggies tucked into the corner of the room whose only inteeraction with anything is when the big hand opens the cage and fills the bowl every few days.
The same thing goes for all of the reptiles, hermit crabs, betta fish, and other small animals. Alot of them are bought on implusse by someone who has absolutely no idea how to care for them, thinking that, "they'll learn as they go."
And the fact is that most breeders just do not care where the offsprig go. They do not have the time to be going to everyones house, or asking a bunch of questions or whatever. Also, people lie and there is even less time to figure out what intentions the potential adopter really has for the animal. They care about getting the "adoption fee" for them, what happens to them after that is not really of concern.
As for the pit bulls, I agree that it is how they are raised. Last night I saw someone standing with one outside of the grocery store. She kept yelling "sit down!" and kicking it (hard) in the belly to get it to sit. I thought to myself, "I am going to see this dog on the news someday." Poor dog. It is the reason why there are as many dog attacks here where I live than there should be, people believe that if you hit and punch the dog, he will listen to you and see you as dominant. They are mistaking fear for dominance.