Re-reading my post, I see a weakness is where I describe this as a case of "arbitrary refusal of service." The religiously inclined, or those who see primacy in individual conscience, would likely disagree that this is by any means arbitrary.
What makes it arbitrary, I believe, is the grounds for justification. We cannot justify it simply by making recourse to individual conscience; we must still be able to defend the claim itself. If a matter of fact can be established, then it should be observed as such. If it becomes a matter of value, then we should land on the side that has the smallest practical negative impact. For example, we shouldn't agree to a value that will undermine the co-operation of individuals in fundamentally co-operative contexts.
Now don't make me defend fact-value distinction or what a fact really is. I'm not ready for that.