Everyone is talking about this and I have yet to hear what I think is a very strong counter meme to the "freedom of religion" meme.
That counter meme runs like this: Employment is an economic transaction. It's an explicit or implied contract. That contract spells out what the employee provides (a specific kind of labor) and what the employer provides (compensation).
You provide your labor and the employer controls it: where you work, your hours, who you work with, the kind of work you do.
The employer provides the compensation (money and benefits) and you control it.
The employer's control over the employee ends at the factory gate. The employer does not get to follow you home and into your bedroom at night. The employer cannot tell you how to spend your money, where to take your two weeks paid vacation, or how to use your medical benefits.
We have laws that keep it an arm's length transaction, in the event there is an employer who wants to get involved past the factory gates. They cannot stipulate that your salary cannot be used for contributions to a synagogue, or mosque, or the "wrong kind" of Christian church.
They cannot make stipulations about where you take your vacation: they can't prevent you from making a religious pilgrimage, or from going to Las Vegas.
And they cannot follow you into your doctor's office and make decisions about your health care.
I think that for people who are on the fence about this, pointing out the power disparity of the relationship, and that this is like any other economic transaction would help them frame the whole thing differently, and in a way that respects the individual liberty involved.
You have the opportunity to make the argument to 1000s of people in comment threads in your local paper. Remember the rules: you are making a case to the reasonable middle, the majority of whom read but don't comment. Don't rise to the bait of people who call you a "lib" or say other things that make your blood boil. You are talking to the people who are still persuadable, and you are giving them another way to consider the issue. That's the most effective thing you can do to change minds.