Because, as we all know...
In the Qur'an, Allah I has commanded us to wash our feet while making wudu...
Go ahead and read it... ...the detail is mind boggling.
To wit -
The proper way to wipe the socks is to place the first three fingers of the hand on top of the foot (by the toes) and slide them back to the top of the ankle bone. The right hand hand should be used to wipe the right foot and the left hand for the left foot.
Don't be gett'n it ass-backward, now !