True enough, but...
Well, depends on how you see it. Using implied empirical evidence, the following could be said:
On the tabletop, the size of a slotta-base is 1 inch. It’s widely known that the base is roughly 5 feet wide to scale, making a Space Marine their average 7 feet, So in combat speed, a Space Marine moves 6 inches, and charges 6 inches. So, they can either walk 30 feet, or run 60 feet. Unless your vehicle is a skimmer, it will only move a maximum of 12 inches, or 60 feet in that same turn. However, the rules don’t give an average time in seconds that a turn would take in reality. I wouldn’t think it would be more than 10 seconds or so. So that is pretty slow.
But if you watch the test animations that Exile films has on their website for the Bloodquest movie, Space Marines move much faster and more nimbly than any Storm Trooper I’ve ever seen. But then they are between 7 and 8 feet high depending on which model you’re using as a scale, that would give them a huge stride.
Of course then, they also have giant banner poles that prevent them from even walking down a corridor of an average Star Wars Imperial hallway, too!
And then there’s the reference to the shooting, which the Space Marines excel at, and the Space Marine armor, that not only protects them, but doesn’t explode and burn when hit with an energy weapon.
It can go on for much longer, but you probably haven’t even read this far without getting bored to tears.