I’m not treating it as a knife in the back. It’s always good to have a spiritual health check. (2 Corinthians 13:5). My response to that question was to pray and make sure that I could answer in the affirmative.
Is it a loaded question? Undoubtedly. Passive-aggressive and saturated with judgment and accusation? Quite clearly yes. Does he use some new meaning of the word “Christian” of which I was not previously aware? I think that it’s pretty clear that he does. Is it a question being asked in bad faith? I’m pretty sure it is. But the whole purpose of things such as that is to goad us into a reaction, by getting us all defensive, prickly, and offended. By getting wound up and stressed about it, I would be giving him exactly what he wants.
I think that the best—and most Christian—response to things such as this is to just forgive him and move on. In recent months I’ve realised that getting upset about the effect that bad attitudes to science in the Church have had on my career in the past is counterproductive, because it’s a drain on my time and distracts me from moving forward with my life and career into the future.
In any case, whether or not Adam thinks I’m a Christian is neither here nor there. The important question is whether or not Jesus thinks I’m a Christian.