That's because spears are meant to be used en masse, like you say, when the enemy makes a circle, or a shield wall with spears? A cav charge gets stopped dead in its tracks
One on one though? They're useless, there is a reason spear formations were exactly that...formations (the phalanx for example) a single soldier can't do much
Biggest bunch of bull**** in your comment. If you really want to use historical accuracy then spears were far from useless in 1vs1, the reason it was used in formations is because formations even elevated the efficiency of the spear since it provided the range and ability to ''snipe'' enemies of the opposing formation who weren't directly in front of you. The spear wielding AI also aren't as effective against cavalry as you'd think in the game, did you actually try it out?
The reason the spear is so useless now is because of constant complaints from multiplayer beta testers who seem to have a disdain for the spear for some reason, even though I've personally never had a problem killing ANY player using a spear and the only time it really shined is when someone used it when backing up another teammate while staying behind. The only spears I've seen that could potentially be considered OP is the hybrid spears who could also be used as javelins or javelins which could be used as spears, one of the Khuzait spears comes to mind here.
Some people even used the excuse that the spear is ''boring'' (yes I'm serious, I've personally seen it in the beta) therefore it shouldn't be a good weapon.