So Cenarius has met Broxigar in the new timeline. Then how did he still confuse orcs for demons when warcraft III rolled around? And if he didn't, how did he die?
Well, they had just drunk demon blood. Maybe Cenarius could sense it. Also, they had defiled one of his moonwells, which is bound to make any god of nature pretty angry. He may have been using the term as an insult, the way we might call someone a monster.
Because Warcraft III happens before the books and we played in original timeline, instead of altered one. Or he forgot, just like many details of this war disappeared from Krasus' mind.