How do you explain that it is ONLY ONE SPOT ON HIS BODY that has white hair while the rest is dark? That shows that aging can't be the explanation.
Are you familiar with Occan's Razor? If not, it basically says that the explanation with the fewest baseless assumptions is the most likely to be correct. Apply it to this scenario. Obviously, "God did it" is an absolute bonanza of huge assumptions not just about the situation at hand, but the overall nature of reality, all with nary a shred of evidence in their favour. Bearing this in mind, can you think of any other possible explanations for this guy's white spot? He and others involved in the video are either complete nobodies or known Christian proselytisers. With modern cosmetics, a patch of supposedly paler chest hair isn't exactly difficult to do. Perhaps they're just making it up. Are there any unproven assertions involved in that hypothesis, particularly assertions that contradict objective facts about the nature of the entire known universe? Yes, but far fewer than the "God did it" theory, wouldn't you say? Hell, what if we say he rolled onto a stick of chalk in his sleep? Again, quite a stretch, definitely more so than the "video is bullshit" assertion, but nothing on the level of "an all knowing, all powerful space wizard is attempting to communicate through the power of dreams and psychically fucking with the colour of his chest hair".
Now, do you see why your Youtube anecdotes aren't converting anyone?