I am not understanding your grammar. "itch is us corp so they must" ... "they must credit me". Who must credit you? Why has crediting you anything to do with revoking rights? Giving credit is not the same as copyright. You can't credit someone and suddenly their copyright is void or vice versa, you do not credit them and you break copyright. This is not how this works.
You did not say either way about your credits being removed. You only complained about being removed "from contributor list". Which, on Itch unfortunately is the admin list. They really should separate those functions.
It is good that this has been resolved.