I think "reasonably attainable" would be a better descriptor in this case, as the extremely literal meaning of "obtainable" is much closer to "this thing does in fact exist and somebody can eventually get it somehow" than "somebody can get this without gambling his or her left arm and eyeball for it".

Really though, is it that hard to figure out the guy means "obtainable within reason"?

Personally, I'm fine with anything other than Voidwatch Rare Item Drop Rates of Depression for the scrolls. Hard to obtain that's comparable to working in a coal mine is fine by me. "Hard" to obtain that's comparable to playing the lottery over and over is not so fine.