I think this is a bad idea. For starters, Christian Exodus overstates the problem. But the bigger problem is that it expects more political action from Christians than I’m convinced is Biblical.
We talk a lot about a culture war. But there is a much more modest Biblical view of success here:
1 Timothy 2:1-2 I exhort therefore, that, first of all, supplications, prayers, intercessions, and giving of thanks, be made for all men; For kings, and for all that are in authority; that we may lead a quiet and peaceable life in all godliness and honesty.
We may fight a culture war, but Paul here seems to be happy with just being left alone. Sometimes I wonder if that’s not a better course.