I don't agree with the 43% number.
There may be 43% of Catholics who believe that gay couples can have "civil unions" through civil ceremonies which would give them the tax benefits and legal rights of civilly married couples, but I think that few, if any, Catholics would want the Church to be forced to perform religious ceremonies for gay couples....
And in the case of gay marriage, most Catholics don't have any skin in the game.
With the whole HHS mandate, there is a concern that it's all just providing ammunition for those who want to eliminate healthcare altogether, even Medicare. That "ammunition" that the bishops are loading their guns with, are aimed directly at the uninsured and underinsured and everyone who will someday reach the age of 65.
They would rather see all of us drop dead in the street than allow an insurance company to pay for contraception.
But in the case of gay marriage, they can complain all they want, but they aren't giving proponents ammunition that could hurt us or make us drop dead in the street.
That's the difference.
It is easy for Catholics to be against "religiously sanctioned" gay marriage, because there's no downside.
It's hard for Catholics to be against fighting the HHS mandate because the fight is ammunition for knaves and blackguards and devils to rescind the health care law with.