except they are NOT convinced by them. They're accepting rationalizations of the religion they already hold.
That's his target audience, people who already believe the conclusions he comes to, and buy multiple copies to send to insufficiently pious relatives and friends.
He claims to have been an atheist researching both sides of the question, but he only gives voice to one side. If he 'fell for' these arguments in the first place, as he claims, he must have either only researched one side, or only gave credence to one side. Meaning he was already a believer, not an atheist, when he started 'researching' the two sides.
That seems to be extraordinarily flawed logic on your part. Why would it be that if you study both sides of an argument, you need to be convinced by the most reasonable and backed up arguments instead of the shittiest ones? If that were the case, there wouldn't be any global warming skeptics or 9/11 Truthers. Many of them DO look into it, research both sides of the argument but end up being convinced by the dumbest ones. They aren't lying about what they believe and they aren't lying about the fact that they researched both sides of the matter, they just ended up applying poor reasoning skills to that research.
If you became a 9/11 Truther because you thought that steel can't melt and therefore it must have been bombs bringing the buildings down, you're
actually a 9/11 Truther. You're not some kind of fake conspiracy theorist because your reasoning is dumb. If you later read an article about how Illuminati members ended up losing a lot of money because of the attacks and think "Oh, well I guess that means they didn't really do it since they wouldn't make that type of mistake, so it looks like it was an Al Quaida attack", you are then
actually not a 9/11 Truther at this point. You're still an idiot, of course, but you're not the type of idiot which a given label applies to.
Similarly, researching both sides of the Christianity/atheism question, there is no reason why somebody couldn't dismiss a hundred legitimate arguments because he simply doesn't personally find them compelling and then watch a clip of Bill O'Reilly saying "Tides go in, tides go out - therefore God" and think to himself "Oh ya. I hadn't considered the tides. That angry rapist makes a lot of sense. I guess God must be real after all". It would be a stupid piece of decision making, of course, but there's really nothing which prevents decision making from being stupid.
You're saying that Strobel didn't make stupid decisions, he lied. Your reasoning as to why this is the case seems to be very flawed.