If you have fed birds for any length of time, you will soon realize that there is no such thing as a squirrel-proof feeder. I'm speaking from years of experience in that area; even the extremely expensive pagoda-shaped, squirrel-proof feeder that I bought from Wild Birds Unlimited was soon shredded to pieces by their tiny sharp teeth. From that point on, I've always made a point to buy inexpensive feeders for the winter and I then throw them out as soon as spring starts.
I don't begrudge the squirrels their food as long as they leave some for the birds. And I didn't have any hopes of a $10 "squirrel-proof" feeder even coming close to truth-in-advertising. But really, did the squirrel have to be quite so blatant?