I presented a very simple argument to a young-earth Baptist minister when I was in college:
When I look into the sky at night, I see stars that are hundreds of millions of light years away. The light has taken hundreds of millions of years to reach Earth, indicating that there is a past at least hundreds of millions of years old.
He replied, "In God's universe, the speed of light need not be constant." (Just ignore the ridiculousness of what it would mean if God sped up the light between here and there and what that would mean for the future of light coming to us. Ignore that part.)
"OK, true," I replied, "but why would God show us a past that does not exist? Is God trying to trick us into believing the universe is millions or billions of years old? Is God a god of deception?"
His answer? "Get out of my office."
Now, I'm a follower of Christ and faithful to God, but that experience - and others similar to it - have led me to believe that young earth creationists are not interested in getting at truth, only to reaffirm their own beliefs. Need further proof? Read a book like "Scientific Creationism." In one chapter, they present an argument like that in the original post, designed to cast doubt on radiocarbon dating because of uncertainty around decay rates. A couple chapters later, they will use decay rate science to claim that the earth must be young based on the presence of certain elements on Earth because - you guessed it - the absolute nature of decay rates indicates that these elements would all be gone if the earth was old.
Sigh.