There are better and worse reasons for voting to leave and voting to remain. Thus, it is the responsibility of evangelicals to find the best in the arguments they disagree with.
There is a danger when Christians try to play a trump card, such as: “My case is better for missions”; “my case is better for defending Christian freedoms”; “my case enables me to love my neighbor”; “my case frees us from secular un-Christian institutions.” These arguments try to shut down debate. You can love your neighbor and want to vote to leave. And you can believe the EU is a deeply secular institution often intolerant towards Christians, and still believe that membership is best.