You probably know enough to realise that's a controversial opinion.....
That's like telling the person that says lemons are yellow "that's your opinion".
Yes 3500 calories equals roughly 1lb but that doesn't mean that 1lb is (all) fat...
*edit*
To use a analogy, it's similar to when you start Photography. Before you start, you believe it's megapixels. Then you buy a camera and start snapping away and realise the basic fundamentals is pointing the lens and clicking the shutter.
As you progress you realise that although that will equal an image, that doesn't necessarily make it a good image. To make a good image you need to know about exposure, dof, aperture vs focal length, how to manipulate light, angles, leading lines etc and then you realise "oh... so it is more than just point and shoot".
The same can be said for the current topic of conversation, yes, calories in vs calories out will make the scales shift. But that doesn't mean you'll get the result you want.
No one can debate that calories equals weight.
Same as no one can debate if you press the shutter, you will end up with an image.
Similarly, no one can debate you will need to know more than that if you want better results.
And into the current discussion, the biochemistry that is involved in weight loss is much deeper than is currently put to the average person wanting to lose weight... why isn't it common knowledge? ...perhaps the same reasons we still sell camera's on megapixels - it's just easier for people to "get".
I don't in any way mean to sound condescending, no way hosay - I just want to put it out there that it is in fact more than calories in vs calories out.