I think there are different types of affirming parents.
The first type is like @anyolddinosaur described, they are frightened and confused and genuinely want the best for their child, so they obey the professionals who tell them transition is the answer, after all they are the professionals right?
The second type is like a Muchhausens parent; they enjoy having a child who is different, with a very high profile 'condition' (trans) that no one can criticise. They love the attention and validation. Jazz Jennings' mother is this type I believe.
The hird type would honestly rather have a surgically altered 'stight' child than a same-sex attracted child. Little Jonny likeds boys, can't have that, let's turn Little Jonny into a girl. This is the saddest type in my view. The mother of Kai Shappley is of this type I think.