It’s not backwards. It’s actually correct vexillology.
Flags don’t have a right-to-left, they have a hoist (the flagpole half) and a fly (the other half)
When rendered on print/screen, a flag has the hoist on the left and the fly on the right typically. HOWEVER, when rendered on moving objects, such as vehicles or clothing, the hoist is always at the part facing forward. Mentally draw a flagpole attached to it and figures walking in the same direction the shoe would be walking if someone is wearing it. Then it would make sense.