Why am I not tacking when I gybe???
'Cause that's the terminology.
When crossing the wind while going to windward, it's a tack. When crossing the wind while going downwind, it's a gybe. The differentiation and a thorough understanding of the relative wind direction and it's effects can be the difference between killing someone (being hit with the boom during an unplanned gybe) or a bonk (being hit with the boom while tacking).
If you tell me "prepare to tack", I know instantly which direction you're going to turn and what to expect from the wind and sails. Tell me "prepare to gybe", and I'll expect something entirely different and I will prepare the boat differently. The terms have meaning and are not interchangeable.
IMO, "Helms alee" is an archaic term and should only be used on a boat with a tiller, if then.