This is typical internet nonsense. People repeat stuff that they read on the internet but usually they have never even shot a 45 Colt.
I have both a 45LC and 44M Redhawk and I can reload them to the exact same velocity with the same bullet weight. Guess what? They recoil the same and I can't tell any difference in "ear splitting muzzleblast".
Another good one is when people say the 45LC has less recoil, except they fail to mention that they are comparing 44Mag factory loads with 45LC cowboy loads, and since they don't have a chronograph, they have no idea that the 45LC loads are running 300 fps or more slower.