You're ignoring that the court doesn't give a flying monkey turd for either or any parent.

They wish to protect stability and continuity for the child.

It obviously stands all over the western world as the correct way to prioritize.

It is of course deeply unfair how the mother has treated the non-father/father, and how the biological father has got off scott free.

But none of that is the childs fault, and the court won't do anything that might damage the child.

Legally, any other point of view doesn't stand, and it is, I think, absolutely justifiable from that perspective.

"sorry mate - I'm not your real dad - all those years were a fraud - I'm off and I'm taking my money and love with me."

That would be pretty shit don't you think?