"Seems"? one can look up the "real" Wilton vises at least and see that they are made of a high-strength cast iron. Some refer to it as "nodular" iron. Thus the reputation as others have mentioned of being able to take a beating.
I did not look at the wilton site but would guess they, like most manufacturers, now have a cheapo line that is not as strong as their good stuff. A "real" Wilton can still be had new but costs WAY more than that kentool thing.
As a side story - i do have a Kentool tire spoon. After some use i thougt it was a good thing. But then on a larger tire, i actually bent the spoon!!! Just using my hands to push/pull on it! I have, since, not been impressed with kentool. My Horrible Freight spoon, while less functional because of its strange shape, has yet to bend........