I think it's more of a fight for true equality and critical thinking skills than it is pushing our beliefs onto others. Fighting to allow atheists to hold political office is not pushing beliefs onto anyone. Fighting to allow lawful marriage between any two consenting adults is not pushing beliefs onto anyone. Fighting to take Christian prayer out of public schools attended by more than just Christian children is not pushing beliefs onto anyone. For every atheist billboard, there are thousands of Christian billboards and crosses clouding the horizon. Letting others of a minority known that they are not alone is not pushing our beliefs onto others. In fact, for many of us, if religion would keep out of the lawbooks in which we have to abide by and stay within the walls of church and private homes of families and in the hearts, minds and souls of the individuals that choose to believe, then you'd hardly hear a peep out of us.
Pushing gay marriage is an issue of equal rights and to deny these rights in the name of religion and defense of marriage sanctity is disgusting and sadly amusing considering there are no protests outside of divorce courts.
Pushing an equal but differently named union would be equal rights but that option keeps getting turned down by the gay marriage supporters. It would be the simplest and the most common sense way to handle the whole issue and a compromise that everyone would dislike equally but it would work.
As for protest, did you notice what was going on in France about a week ago.