No, I'm claiming that it should not have been surprising that the agreement for someone who worked there included such claims. How I personally feel about it is irrelevant; it's a standard practice, and to be expected.

What I am arguing with is your repeated use of terms like "visitor", to make it sound like the guy just popped in for lunch one day and they claimed all his work. He worked there. They trained and taught him. While there are contexts in which "visitor" can be the appropriate term for that (again, see "visiting professor"), the usual connotation of "visitor" is incredibly misleading here, and I wish you'd be more clear about it.