Comfort And Happiness
They knew there was no facility capable of taking care of all of them. They had gone through the worst, so everyone only wanted the tortoises to be happy and comfortable. This was the least they could do for the critters!
Their Entire Lives
It turns out that the tortoises could not be released into the wild like that anyway. They have spent nearly all their lives in the abandoned house. Releasing them into the wild would only put them in danger of dying or getting caught by poachers once again.