Yes, it's intentional. Weapon stats are based on the weapon used, not some arbitrary decision about "balance", it's shorter than the lance used by the Xystophoroi. Lacking power_charge, their primary attack is significantly worse than that of Xystophoroi, or any other proper lancer cavalry. The secondary spear is often worse than the kopis used by other lancers up close (and they have that because they didn't used to have a secondary weapon at all, which made them useless in melee).
If you don't know why Hippeis and Xystophoroi both exist, try looking at where you can recruit them. They are different regional expressions of medium cavalry, Hippeis are the older Greek form, Xystophoroi the more "modern" Hellenistic form.