I am sorry you are unimpressed with the argument presented in the article you found at my web site.
Here is my response to the dragon in my garage argument. From a naturalist perspective this argument makes a lot of sense. If someone is to make a scientific claim, this argument is perfectly valid. If you know the history of science well, you will recognize that this argument could have been used to create skepticism about the existence of "anima" of "phlogiston" of "ether" of "calor" and other substances created in the history of science to explain otherwise difficult to understant phenomena. Of course, none of these substances turned out to be real. I believe that "strings" of string theory and multiverse theory also ought to be challenged on the dragon in my garage argument as well. Scientific claims need to hold up to the dragon in my garage argument.
However, as an argument against the existence of God, I believe it is NOT a valid argument. I know of no one who believes that God can be detected by any science experiment. If we apply the dragon on my garage argument, then let me list a number of things which certainly do not exist.
3. human consciousness
I am guessing that you believe that some of these things exist as real things, yet that they are not physically detectable things. If you are a true blue philosophical naturalist, then you do not believe any of these things exist. My experience is that philosophical naturalists are almost never true to their philosophy in the final analysis. Because God exists as a supernatural entity, he will not ever be detectable by any scientific experiment. I believe that I am quite honest about that in the article you find so full of fluff and backward talk. I have never said that God is a scientific proposal, neither do I claim his existence as a scientific theory. Naturalists want the existence of God to be a scientific proposal. It is not and no amount of yelling and screaming on the part of naturalists will change this fact. They cannot have it both ways. If we exclude God on a-priori grounds, then we must not try to use this as a basis for "proving" God does not exist. Such circular reasoning will not fly.
Bottom line, Sagan’s argument is not a reasonable argument against God at all.
Now, you may choose not to believe in God. I honor and respect your decision. I will say this. If you take as a presupposition that God cannot exist if he cannot be detected by a scientific experiment, then you are building your belief system, not on the evidence, but on a presuppositional position, and I will guarantee that with this philosophical (not scientific, but philisophical) perspective, you certainly will not find God. I do not say this to put you down or to ridicule your position. I believe your position is a reasonable one, but I believe it is worthwhile pointing out the presupposition and the limitations imposed by this presupposition.
My father was a believer but my mother was not. (She said she was, but I see no evidence now that she believed in God at that time). Since that time, my mom came to the point of having faith in God. I received no pressure whatsoever from my parents. When I went off to college I was (or at least I claimed to be) an atheist. So you can count one empirical piece of evidence against your theory, but I have a feeling you will find more examples which support your theory than ones which oppose it.
"let me make up my own damn mind" I detect some anger here. Hopefully you will be able to transcend this anger so as to reach conclusions based on reason rather than emotion.
Good luck with your search for truth.