If the long-legged/tall people are putting in the same effort as short-legged/short people and all other factors are identical as well, then yes, the long-legged people would be faster, simply because longer legs would lead to a longer stride.
In practice, it's not nearly as direct. The tall person could be less fit, could feel more comfortable taking shorter strides, could have some sort of problem with their legs, or the short person could be one of those "always hurrying" types, etc.
There's also a psychological factor of sorts. People have noted I walk a lot faster and do so for far longer if I'm listening to music than if I'm not--because I'm not concentrating on the distance I've gone/have to go, most likely.