Vengeful cry does not affect allied mercenaries

Rage on hit searing exarch implicit on gloves does work with mercenary and shows rage effect on mercenary.

Because gloves show rage on mercenary, I assume Vengeful cry also should show rage on mercenary if it worked.

Despite the wording, Vengeful cry doesn't work with mercenary.
Gem description says "allies", not "allied players", and mercenary is not a minion, thus I expected it to work.

Tested Vengeful cry with Redblade Banner, player character gets rage and rage effect, mercenary gets nothing.