Same thing with these stupid Event weapons, the tooltips say they scale, you can join at 10, but the weapon requires level 30
I think at this point, it's safe to say the devs are putting 100% of their effort into polishing SL so it doesn't end up like BFA, leaving most bugs currently in the pre-patch unfixed...
The logic behind scaling tech was to include all player in on the fun. Blizzard doesn't seem to be sticking to their original reason for making the scaling systems. From what I can tell scaling limitation are rather arbitrary.