And my bolded part does not do that. Anyone can kiss; they don't have to be homosexual. If I want to try for a 15% discount, I can kiss my brother or male best friend, even though I'm not homosexual. Now I DO find that offensive because it is distasteful to me ; I have no desire to kiss another male, although a certain percentage of the population does do that. But I would have to do something that I find offensive to qualify for a discount. I don't want to base a counter argument on same-sex. It can be a variety of things. This would be entirely different it were a discount for being polite (for example, thanking the wait staff). However you color it, this is largely a Christian-based practice (saying grace). And by saying "anyone can do it" you are saying atheists or non-Christians have to perform or fake a practice which is primarily Christian based.
Tell you what, since religion is the basis of this discount, how about a restaurant in SL offering a 15% discount if they see a Book Of Mormon on the table. Doesn't discriminate; you don't need to be Mormon to bring in a BofM. Anyone can do it.
And keep in mind, I'm posting this as an active Christian. I just completely disagree with that policy.