Can't think of any other reason for that hole. Water will always seek it's own level, so in a wringer washer it will be going down, not gushing upwards.
All wringers/mangles hand or machine operated required periodic few drops of oil. On Maytag conventional washers some parts are packed in grease, the roller bearing needs a drop of oil every several weeks depending upon how hard used. But Maytag's wringers open up like a clam so easy to get at spots that require.
Those oil holes are quite common on many older appliances; motors, gears, etc... Before better quality greases/oils came on scene allowing "permanently lubricated".
With a wringer/mangle due to nature of work involved there is a constant exposure to water. Worse that water will be laden with detergents or soaps, so sooner or later whatever lubrication at certain exposed points will need refreshing.