"Why do men need a campaign for more involvement in families. Surely they can negotiate that with the women they are partnered with."
Well, if we assume we live in some magical world where everyone always negotiates in good faith and everyone always works towards solutions that solely hold the child's best interests first then, yes, such negotiations can be guaranteed to work. Back in the real world, however, some people don't/can't do that and that's when it gets difficult.
As for the CSA, you'd have to ask FNF that. I think their stance is that as courts see finances as separate from contact, then as an organisation that is interested in contact issues they don't want to get bogged down in financial stuff. For what it's worth, though, I've never seen any hint from any FNF official statement or member that maintenance should be witheld for any reason.
"I didn't post the link for you, I posted it so everybody else here could be aware of FNF stances."
Gosh, that's a funny way of spelling "Actually, you're right, they don't say that" 