Every game has its 2% or so of players who simply learn at the lowest possible rate. Knowing about AP means visiting the character sheet, and clicking on each tab at the top in order to see what it does. Anyone familiar with how internet browsers work should already be familiar with this and at the very least, understand there is an interface here that allows them to allocate points, even if they dont understand what makes an optimal/viable build.
Its likely the OP ran into the small percentage of folks who either missed this, or possibly some folks who are purposely rectricting themselves in order to increase challenge. To have 2 in the group at the same time is likely a rare coincidence.