I agree that advancing the designer theory does not really resolve the problem of HOW life originated, because it merely rephrases the question to: HOW did the designer DO it? + an extra problem is created: Where did the designer come from? A question we will never find answered unless the designer reveals himself in an undisputable way.
That is however no reason to reject the theory. It is not because of doubling the problem, that it becomes unacceptable or impossible.
To illustrate: we will never know how the 1st wheel came about. But nobody doubts that somebody invented it. It was designed, and we don't know where the designer came from. It is not because the answer: "somebody designed it", is actually a doubling of the problem, and not really a solution, does not mean it is not true. It is a key to the solution. To find the answer, we will have to start searching for the oldest wheel. As the earth is quite old, there are many traces of all the life forms and sequences of them, with other words, it could be possible to find some of the designer tricks used, bringing us closer to the HOW-answer. That is one side.
On the other side, to prove the anthropic principle, there are 2 necessary conditions.
1st. Scientists will have to prove that they can build life from dead material on purpose, influencing directly the process. We are closer to this than ever before, I must admit.
2nd. After this, they will have to prove that the necessary conditions, to bring all the building blocks of this life form together with the triggering mechanism of it, could have happened spontaneously.
If both conditions are fullfilled, we will finally have reliable data to start calculationg how much CHANCE there is that this happened, and only THEN, the anthropic principle can be used. As far as I know, there is not enough data available, as both conditions are not yet fullfilled. But maybe I did not do my homework well enough, and scientists might have made progress in this fields.
Ruling out the designer theory, is throwing away one of the keys to the answer of one of the most important questions one can ask. I am not convinced I should throw away that key, as there is much in nature that speaks against it.