No, it does not say you can use Kleins. You know what, I use them every day.
Occassionally I do buy Ideal's pliers but they are like $10-$15 more than the Klein so I usually go with the D2000-9NECR.
Yes, they look exactly the same and do exactly the same job. The fact that it is impossible to remove one of those crimps tells me it is doing as good of, or better, job than a greenie.
I don't let things like this bother me. I am very conscientious in my work and if I felt at all uncomfortable with anything I was doing I wouldn't do it.