GM I am on vacation with a widowed friend of mine so not reading or posting much, but I read this and agree with all you said.
We need to share negative feelings - my widowed friend has been sharing her grief, and it is an important part of the true healing process to discuss our feelings in a safe place, as most of the time we cannot share them, even with close family. I feel the same - of course we do not 'expect' thanks or appreciation from these guys, but they are the parent, and it would be nice. It is actually healthy to expect good behaviour from people!!
And my widowed friend is a lawyer (not divorce!) but she agrees that no fault isn't actually fair if one person walks away. If this were a business deal there would be penalties