Isotropic magnets have no preferred direction. Since the orientation of their magnetic grains is statistically random, they can be magnetised in any direction. However, only those magnetic crystals are magnetised that are oriented in the direction of magnetisation. The shape anisotropy possible for isotropic ferrites is remarkable. Depending on the powder properties and the moulding process, it can be up to 10%. The main reason for this is the hexagonal, laminar structure of the powder, which can orient itself in the compression direction upon axial pressing.
This can be compared to the difference between pairs of dice and a deck of playing cards. If we toss each “systems” onto a table, the dice will be oriented stochastically, that is randomly, because of their shape. Quite a contrast to the playing cards; they fall in a distinct flat pattern, which will be further intensified if you apply pressure to them.