You are both correct, and here is why;
Different ammo will work best with different barrels. It has nothing to do with hyper/high velocity, but more about the rate at which the powder burns for that barrel in combination with chamber pressures.
Hyper velocity in a 16" barrel would mean a different type of powder type and amount to the same velocity on a 22" barrel for example. The design limits of the .22lr will quickly decrease the available potential of each barrel length to the point where it does not matter anymore.
In contrast, the powder and charge of a commercially available ammo (like the Velocitor) can favor a certain length/chamber/twistrate of barrel and is very deceitful because of that. Even then, it can vary slightly from batch to batch.. especially in cheaper ammo like wilcat etc..
Like I said, pick the barrel length you want, then get the ammo it likes. Period. If you want accuracy, look at the chamber type and what action it works best with.