Yes, the difference is that the folks who subscribe to the notion that the speed of light (in a vacuum) is a constant have real degrees in physics and Astrophysics, unlike your source: "Chuck Missler, Ph.D, B.A. all that good stuff in astrophysics ..." [snip].
A persual of his own website indicates he has a masters degree in engineering and a Ph.D. from a Baptist school which one can only presume is a divinity degree or something related thereto. There is not a single piece of information on his website to substantiate your claim that he has ever taken a course in Astrophysics, let alone holds a degree of any kind in it. In short, there isn't any evidence that Mr. Missler is a scientist of any kind.
Since you seem to have trouble getting facts straight, I'll be brief. That the speed of light is constant is a scientific reality accepted by the vast preponderance of the world's scientists. You have opined that is isn't. You offer only your personal observation that "things decay" and the unsubstantiated claim that the speed of light was previously measured at 200,000 mi/sec.
You are the one making the extraordinary claim, not me. You are the one who has the burden of providing extraordinary evidence to back up your extraordinary assertion.
Please provide us with compelling evidence that protons, photons, neutrinos, and electrons decay, and that the speed of light was conclusively faster in the past than it is today. Cite the original sources, if you please.