Writers are frequently asked why they wrote their first book. A more interesting answer might come from asking them why they wrote their second one.
In conversion you are not attached primarily to an order, nor to an institution, nor a movement, nor a set of beliefs, nor a code of action - you are attached primarily to a Person, and secondarily to these other things.
I have legs of iron, but to tell you the truth, they're starting to rust and buckle a bit.