Violence is about physical harm. Therefore an extreme but ultimately non-violent political agenda does not fall under violent behavior. Unless the definition of violence has changed since I last checked.
The wider debate around same-sex marriage covers a number of issues involving use of force:
- whether a landlord should be able to evict same-sex couples for violating "roommate" clauses in their lease.
- how custody should be determined for children of a relationship where the custody is in dispute (usually between the deceased parent's partner and the deceased's family).
- how a deceased person's assets should be divided up on their death, including things like homes jointly owned with a same-sex partner.
All of these questions potentially involve denying someone something of great value that they would otherwise have a right to. All of the answers to these questions are backed up by at least a threat of force on the part of the state... and if you don't believe me, try refusing to move after getting an eviction notice and see what happens.
The same-sex marriage debate isn't just about differing points of view. When it becomes a question of law, it's about whether the state, i.e. the entity with a near-monopoly on the legal use of force, should be able to
impose one view on everyone else.
IMO, if you're talking about using force (or the threat of force) to take someone's home or children away from him or her, you're talking about violence. The mere fact that these people are trying to get the state to commit the violence on their behalf instead of getting their own hands dirty doesn't mean that their actions aren't inherently violent.