That is incorrect as the fine tuning argument makes us reasonable to assume that this fine tuning is more likely the cause of an intelligent agent then just blind chance, just as the integrated complexity of life gives us more then valid reason to assume that Life itself was brought about by some form of intelligent mind behind it all.
Now is this 100% knock down drag down proof? No. But what we are talking about here is inference to the most reasonable and best explanation.
The fine tuning argument is not in the least bit convincing, mainly because it contains a number of unjustified assumptions.
First off, we don't know that we are the only universe, in fact the evidence that we do have points to a multiverse existing. If that is indeed the case, then the laws of physics and other properties of a universe could very well likely change from universe to universe.
From there, it's inevitable that some universes will not be able to support life, other universes would be able to support life as we know it, and even others may be able to support types of life we can't even comprehend. Going by the anthropic principle, we would expect to find ourselves in a universe in which we could live.
As an alternative viewpoint, if this is actually the only universe, we don't know that the "finely tuned" settings could be set any other way. Maybe it's impossible for a universe to form if things aren't the way they are. In which case, it's inevitable that the universe would form as is.
And realistically speaking, if this was the work of an all powerful, brilliant creator who designed the universe with us in mind, he did a horrible job of it. The only place that we are aware of in which we can live out of the vast expanses of the cosmos, is a single planet. And we can't even live on vast portions of that single planet (i.e. the oceans, or the polar regions). If there are any other habitable planets, they're so far away it's quite possible we'll never reach them. There are untold billions of galaxies so distant from us, that we can never get there. This is not the work of an intelligent designer.
And besides, how on earth would a super-powerful, all intelligent being simply pop into existence in order to create the universe? God is not an answer, it has no explanatory power because we don't know what it is, and you can't even justify it's existence.
I'll give you something to think about as well regarding fine tuning. Your genetic code is one of a kind, and for it to come into existence, not only would it be required that your mom and dad got together, but one specific sperm cell out of the millions (trillions?) that your dad produced over his lifetime would meet up with that one specific egg that your mom happened to release that month. Those by itself are extremely long odds... think of it, if one other sperm made it to the egg first, you never get born, and you never come into existence. The odds against that are astronomical.
But then consider, for your parents to come about, that exact same scenario had to happen for both sets of your grandparents, and your mom and dad had to happen to meet each other and fall in love. Same goes for your great, and great, great grandparents back for thousands upon thousands of generations over millions and millions of years since the beginning of life. If there was one hiccup along the way, you would never have been born. Your genetic code would never have come into existence.
If you went back to the beginning of life a billion years ago or whatnot, the odds against you ever being born are so astronomically absurd it would be incalculable.... But here you are, and here I am, And here are the other 7 billion people with a "finely tuned" genetic code that this scenario also applies to.
In short, just because something appears finely tuned, or the odds against something "finely tuned"
appears astronomical does not necessarily mean it's all that unlikely or abnormal. It may in fact be inevitable.