*sigh* oh boys...
well, i see that it could be both. on one hand, if you're talking about the term "inhumane" as describing something appalling that a person is capable of doing, then yes, humans can be "inhumane." examples of this as torturing other human beings, children, animals...as there has to be something incredibly off in a person's psyche in order to want to cause pain and harm in others and take full pleasure on it.
secondly, if we look at the term "inhumane" as just something a human does...well, if a human is doing something, anything, then whatever he/she does is human...even if considered "inhumane".