I haven't found that this is necessarily true. I adopted a kitty that had been living with a feral colony. The first few weeks we never even saw her but when she realized it was safe, she would come out. She still hid out at night for months. Almost six years on and she's a total lap cat! She sleeps with us, she follows me around the house like a little shadow, she even sleeps with and plays with her cat roommate. Every once in a while, she'll still hide out somewhere for several hours. And, when I find her, she doesn't display any fear. She doesn't avoid my touch, growl, or hiss. She purrs and leans into my pets. It seems like she's just found a quiet, private place for a snooze. I think some kitties who've had a hard life outside just get used to sleeping somewhere private and safe. Jumping to the conclusion that she should be tossed back outside seems rash.