I still find this hard to understand, let's use the animal rights example. I too am big on this. One example I'm passionate about is palm oil and the threat it's use and subsequent need for more plantations has on orangutans. Sure not everyone cares as much as me, but am I going to stop talking about it, posting articles on Facebook etc. because everyone else might not care like I do? No, because the only way to get people to care and want to help is to continue to challenge them and educate them on why it is an important issue.
If we want to see a change in the attitudes towards marriage equality and homosexuals and therefore a change in policy then we need to continue to challenge those who believe it is not 'right' or 'normal.' Challenging opinions or views will be and has been what brings change.