@op, were you trying to hit it with a ranged attack? If hes to close you get disadvantage on the attack. Were some other effects in play? Was a spell cast giving you a malus to your rolls?
Even just needing a 11 to hit is still a 50% to hit. Rolls 1-10 will miss it, simple as that. Each bonus to your hit rolls will obviously make it better by 5% per bonus to hit but still 40% chance to hit shouldnt come up unless its packing some armor and/or if disadvantage or penalties of some kind are in place.
That said I noticed that they deviated from monsters stats in alot of other places as well so maybe they just gave the ogres a set of armor to make the fight abit more challenging?
