I designed this wonky-looking funnel to fit my Squirrel Buster Legacy (and probably similar models), with hooks and posts that make it possible to refill the feeder without setting any parts on the ground.

This design of feeder needs to be located away from surfaces that a squirrel could stand on, so I assume a lot of people run into this problem. I don't really blame the company for making it so cumbersome to operate, because there's overlap between the smartest squirrels and the dumbest humans.