Respect is as much, if not more, about respecting the basic humanity of others as it is about respecting their comfort levels. People love. People in love give affection to each other, even in public. As long as it's tasteful, it shouldn't matter what sexuality the loving couple is.
Also, using the comfort level of others to justify inequality is wrong. I'm sure there were many civil war and reconstruction era southerners for whom the freedom of black slaves was uncomfortable, that doesn't mean they should have stayed slaves to preserve that comfort. I'm sure there are career driven DAs for whom exhonorating evidence being presented in a case that could make their career is uncomfortable, that doesn't mean an innocent person should go to jail to preserve the DA's comfort.