Magic in Heroes of Might and Magic V.

+. noun. the fact of neutralizing/deflecting screams (cries, shrieks, squeaks) *well... you proved this fact yourself (=*
+. requires mana *yes... not everything that requires mana is magic (= but mana requirement is an attribute of any spell)*
-. does not depend on witchcraft *or maybe it does... but it doesn't seem so)*
-. not available to Orcs *yes)*

Although I still don't understand what difference it makes whether these screams (cries, shrieks, squeaks) can be considered magic or not. In any case, this skill will have to be taken into account when considering "real magic" (they don't discuss, for example, the power of the Order of Order by comparing it only with the Order of Order).

P.S.

can a mass bless with +1 attack and 20 morale really be compared?

I think that a comparison with the "prayer" of the Order would be more appropriate here. Even though prayer does not require mana and has a stronger effect (but does not require a separate ability - one prayer is worth three cries).

P.S. P.S.

...hordes don't rule in the late game

honestly, it's a quote from the strategy section of Warcraft fans (=