No, and I don't know anything about them. Who are they?
If they do believe that Tribe Judah is the sole heir to Abraham's covenant, they're obviously in error; but how can that be construed as having "stolen" the name Israelite?
I'm glad you have that opinion. I sense you may be being more limited in terminology that I. When I say Tribe Judah, I mean the remnents of the southern kingdom surviving today known as Jews, whether it be composed parts of Levites, Benjaminites or some members of other tribes that comprised the southern kingdom which was called the House of Judah.
I don't know; I didn't say anything about "stolen". My theory, howerever, since you ask, would be that believing as they do, that the term "Israelite" would be construed to mean only them, therefore not other Israelites, it could be seen as a form of theft. Hence the term "stolen".