they do know it's true, but as stated before it is more for the reviewer's benefit then anything else.

The 12 factions are complete, custom voices, speeches, units, tech trees, balanced, etc, etc.

The other 38 only have bits or peices, but are not complete.

When reviewers pop open the game, they only want them to play the good factions and the good game. Since reviewers will not download mods anyhow.

So they want a 90% review or a 9/10, not the 8/10 they'd get when a reviewer goes, "I liked factions 1-12, factions 13-50 sucked though."

All about marketing