To some people, it is considered to be an "attack" on their intelligence to disagree with them. It's a "confrontation". Obviously, "they" know the "truth" and you are "calling them out", so it has to be melodramatic!
Some people cannot ever admit they are wrong about anything. I have a son and a brother, both of whom will never, ever admit to holding an incorrect belief. If they think that the earth is 6,000 years old, then by god, the earth is absolutely 6,000 years old! You are a "moron" if you point out proof that some rocks are actually millions of years old. That fossils are millions of years old. And that Jesus isn't the first purported "savior" of mankind.
And since many other people have tried to talk to them about real facts instead of what they "know to be true", you are obviously trying to "destroy" them.