I don't care much about celebrities, but it is no surprise that they try to keep a low profile, it would get old fast to have people acting weird and treating them funny everywhere they go. Under an assumed name on the internet they can be treated the same as everybody else.
I know there is probably a lot of famous people on the forums, why not, it is the place to talk knives.
And it is good that some celebrities collect knives, and better still that some portray them in a positive light.