It is important to stop this trend of buying and selling animals and even giving animals away for free on sites which are not monitored. There are other ways which are safer for the animal which can bring the animal to its forever home. When selling are giving a animal away through a buy and sale website you are not giving the animal the best chance it deserves.

It is hard for the seller to check out the appropriateness of the potential home
It is hard for the buyer to know exactly what they are getting. Unless Facebook can comfirm the the homes are pet checked and safe then this should be illegal. 

So I am asking you Facebook to stop this inhumane way of selling and rehoming animals.