I loved it when I saw it. You did a beautiful job!
That said, I'm wondering if your father had specifically asked for a patriotic quilt or wall hanging? If so, then while it was still rude of him not to appreciate your effort and the beauty of the quilt as it is, I guess I'd say he was right to be honest about it.
It does look more like a quilt pattern than a patriotic wall hanging, IMO, even with the flag border. With his "guy's eye," that might be all he sees.
The object of giving a gift is to please the recipient, so if you still want to give him something that will he will be pleased with, get his input when planning the next item. Choose something that takes less effort, since he doesn't appreciate the intricacy you put into this one.
And then we all expect you to finish something else - for yourself!