Next time, give some reasons besides "because it is."
The reason that it's not such a good idea to have so many default hats, is because these hats are NOT separate models.
Instead, they are part of the entire playermodel, meaning all that stuff on your avatar is really one huge model with hidden and colored "nodes" meaning if we added all those hats, the polycount would rise to unneeded levels, causing more lag than we need.