Whilst I agree with you that the whole family are guilty of failing to give Tia the care and supervision she deserved, I feel the bold bit is a bit harsh. There are plenty of decent men out there, who take on other mens' children and bring them up as their own, without there being any horrible ulterior motive.
In my own case, I have 4 children with my ex husband (who is still on the scene and sees them every week - and has done ever since we split up 9 years ago). However, I have a new partner who has been in my life for the past 7 years, and I have left my children with him overnight on many occasions. He regularly cooks for them, gives them lifts and even takes them on days out without me. And, on the other side, his son (with me) sometimes stays overnight with my Ex, along with his half-brothers.