You asserted two statements about "high".
1) "high" means against the state.
2) "high" means committed by a person in high office. (Perhaps you are confused by the fact that the article is about prosecution of impeachment vs. a person in high office? This should not be taken as an excuse to redefine with new limits any legal terms used in it.)
I agree whole-heartedly with #1 and it is in concordance with what I said previously. It would exclude prosecution for "nose-picking".
I disagree whole-heartedly with #2 as, using it as the sole test to determine prosecutability of an offense, it would lead directly to many impeachments for offenses too numerous to list.