There's currently 3 reasons as to why LGB persons can not engage in same sex marriages..
- Historical - People don't like changing what has been for many centuries..
- Religion - Interpretation of the bible though with priests (gay or not) now becoming more and more willing to perform same sex religious marriages without the civil signing.
- Homophobic - Groups that include political, religious and others who use a so called group for the reason behind their actions (The Phelps & Westboro church for example) and trying to hide their own hatred.
Most will use the first two reasons behind their call for not wanting same sex marriages without truly understanding their own viewpoint.