Indeed, it does not appear to be particularly common for "absent" to be used that way, though as someone proficient in English it does not feel wrong. From looking as various language forums, it seems that both "is absent X" and "is absent of X" are not commonly used in English outside of American English, so that is not guaranteed to add clarity. As best as I can tell from reading some dictionaries, it seems to be a mixing of the adjective semantics with the preposition usage. There seems to be better precedence for using words similar to "absent" (such as "without") as prepositions in this syntax, so I expect that the complex semantics of "absent" do not quite work well here.