A fallacy in what way? I'm not sure you are using the term correctly.
I am not positing some sort of argument. I am making a statement. And more than that, my statement is neither misleading nor deceptive. You can agree or disagree, but if you disagree then please present a concrete counterpoint about how my statement is false. Perhaps you are interpreting what I am saying wrong since it is only a one line statement. You an I could even perhaps agree on most points in fact. or not.
Do you know how the Universe came about? If, as your "That's a fallacy" statement infers then you must have a clue how the universe came about. To me such an inference would be a bold statement indeed. I would then have to ask you to qualify this understanding of yours further. Where did everything before the big bang come from? Was there a before? Will there be an after? Is the universe we currently exist in merely 15 billion? What is the nature of time. What is the nature of space as it currently exists? How many dimensions actually do exist? Are we even living in a real world? Are there things beyond the known universe or is ours universe it? If there are other universes, how does ours fit into a larger scheme. Is there some sort of generator of universes or are they merely spontaneous. Have there been recurrent big bangs of our universe?
There are so many questions to be asked and answered. Many of the answerable things are being answered, yet the amount that has been answered I feel is still small compared to the larger questions about the vast unknown. Because we live on one pinprick of a planet in all of this vastness, our ability to determine things observationally are a bit limited because of our perspective. Because human civilization has been around merely some 10k years roughly and of those it has been merely 500 or so years where we have really began to delve into things as science began to take hold, I feel there is much more to learn and find out about the 15 billion year old universe, its origins, and the nature of the great infinite which seems to surround us. We have a lot more learning to do.
Firstly it isn't a fallacy to make an opinion statement, but even more I doubt very much that you can construct a coherent argument as to why my opinion is false. You can merely disagree with my statement, but I am not sure what the point of that would be either. None of us really has a clue since there is much to be learned yet and I include myself in this mass of humans who don't know much. We are trapped corporeally in our universe of apparently 3 discreet spacial dimensions. We are stuck in a universe that theoretically came into existence with a big bang some 15 billion years ago, but we know nothing about beyond the universe or outside the universe. Our knowledge is rather paltry in the grand scheme of things although we fashion ourselves as enlightened somehow.
Is your "pro tip" directed at me for saying that 'none of us from this tiny backwater of a planet have a clue how this universe came about.' Seems a bit of a misguided ad hominem. Especially in the face of such massive uncertainty such as the ultimate nature of our universe and the vast complexity of what exists. Plus you just did the very thing that you were warning about in your pro tip. Seems a bit like Kafka's the Castle to me ending up where you began.
I make no assumptions about people I have never met. There are those who have infinitely greater understanding than do I in all areas of human endeavor, and yet, all of the people I know, are stuck on this one planet, in this 3-d spacial paradigm, with a scant few hundred years of observational data and theory about what our universe ultimately is and how it came about. Last time I checked everything regarding what we know is still theoretical. Humanity seems to be stuck on the same boat called earth and all of our knowledge and understanding is bottled up with us.
If your experience is different that is nice. I think you need to define what you are talking about more before making easy statements like "That's a Fallacy"
Elaboration would be needed if you wish your statement to have heft. but first you would have to know what fallacy is and not confuse fallacy with mere statements and opinions.