If that motivation is to prop up Biblical accounts of man living for hundreds of years and similar such nonsense, then no, we can't trust them. Or rather, I can't trust them. You seem to buy into some of that stuff though. No disrespect intended but you seem to come down on the Creationist side of the coin in every other thread lately. How was Church yesterday?
Wow. Let's break this down.
Valid criticism of an incorrect generalisation yields passive aggression, in the form of "no disrespect intended" -> insult.
I don't even understand what you people mean by "Creationism" - I'm British, remember? As far as I understand it, "Creationism" is the idea that the King James version of Genesis is the absolute truth as regards the origins of existence. This is quite obviously stupid, even though Genesis does get a number of things right (such as the order of animals corresponding with our current model of the evolutionary history of animals).
It doesn't matter whether such "outlandish" claims are motivated by a "religious cause" - if the evidence is there to be observed, then the fact is pretty much undeniable (unless, of course, you're a Creationist). If, hypothetically speaking, a Christian/Jew/Muslim told you that God had decreed that he tell you that the Earth travels around the Sun, would you doubt him because of his religious motivation, or would you test his claim against reality?
To clarify my position on "that stuff", I don't buy into anything
unless there's sufficient evidence/logic to back it up. For example, I'm absolutely adamant that the modern "scientific" method of examining existence is incredibly shortsighted, it relying on the physical capacity of humans and nothing else (though, of course, it's a hell of a lot better than simple guesswork).