We live in a day and age where people can be who they want, believe in who and what they want and pretty much do what they want which is an amazing thing.
Of course as society as a whole becomes more accepting and people embrace who they really are and can live the way they want to live there are some people who resist....or want to attack others for being different. Which is a little silly if you ask me.
There is nothing wrong with not agreeing with someone's lifestyle, religion, sexuality or even religion. What is not ok is attacking someone for who they are because they are the way they are and they can't change that. Who are you to judge someone else? If someone didn't like you because of your race, religion, sexuality, etc would you like it if they harassed you? No you wouldn't.
Live your life by the golden rule: Treat others how you would like to be treated yourself.
I'm not saying you have to embrace it or like it, but at the very least keep your thoughts to yourself as they can be hurtful to people.