> That’s circumstantial evidence, not scientific.
Evidence is evidence. It's not proof, of course, but it's evidence that has to be evaluated, especially in establishing historicity, where experiment is impossible.
> What drives that need? What is so important or dangerous about the object that it must be revealed as a fake to the minuscule amount of Christians out there that believe that it’s not?
This "deep need" is an invention of users. Some people wondered if the object might be the real shroud of Jesus Christ, as it was claimed, or if it is a forgery. Others studied this question using the relevant scientific methods (carbon dating, studying historical sources, fiber analysis, etc) and came up with a scientific answer, with high confidence (but not certainty) it is a 14th century forgery. Literally all of the evidence studied points in that direction, with no credible evidence whatsoever suggesting otherwise.
But, some minority didn't like this answer, and keep inventing reasons why the original investigation (which many of them asked for) was wrong. When we encounter such invented reasons, many of us who care about the truth like to combat it.
So, in summary, it was Christians in the Catholic Church who asked for a scientific investigation of the nature of the Shroud of Turin. The investigation was performed, and it was deemed a forgery. But the Church and some others didn't like the answer of the investigation they themselves asked for, and are now making up facts and methods by which to "scientifically" show that it is in fact a real relic. Some people, both Christian and non-Christian alike, like to debunk pseudo-science wherever they encounter it. That's the whole of this thing.