For me, that's more than a message board post answer. Short answer, I seek people/organizations with wisdom to give me information, so I can learn and form my own opinions. I hear what (s)he says, look at the source they are using, look to see what they are trying to accomplish, digest it, and come up with my own thoughts and opinions on a topic. I then start aligning myself with people/organizations that share a majority of same things I do. Once I have built the trust, I tend to care about and value their opinion over others that I did not find to be as useful to me.
I have that relationship with this pastor, the way he explains things, the way he teaches about the bible, coupled with the first hand experiences I have had that lend me to trust his word and explanation. Do I disagree with him on somethings? Yes. But I tend to believe more than not and have had many blessings. That said, his voice is not the only voice I listen to and use for information. He is just another source, of what I consider trusted, providers that I can use to form my opinion. When we disagree, he doesn't say I'm wrong, doesn't try to brow beat me into believing lock, stock and barrel the same things he does.
Lastly, this church, this pastor is all about what can I do to be better than I was yesterday, both morally and spiritually. How can I serve those that are in need? How can I help those that don't have the same blessings and opportunities I have had? What can I do to make the lives of those around me more enriched? That was the topic of immigration. They are here, for whatever personal reason of their choice, now what can I do to help make their life better for as long as I have interaction with them? The bible teaches, love him as your neighbor, how can I show that love that fits in my belief of the current immigration policy? And what more can I do? There was never talk about politics, there was never talk of this group/person believes this way help get him or her in or out. It was how can I enrich the life of a fellow human while I can?