I've heard people rip yankees and phillies fans for doing precisely this.
That's totally different - Philly "fans" act like they're the greatest fans in the world, like they've always been there and always gone to games; when nothing is further from the truth. The vet was empty when the Phillies sucked for a generation. Their bandwagon fans are not even fans of the team, they're fans of being "Phan bois" They're hypocrites.
Outside of the Redskins, Washington fans have always embraced the idea of spending their money & time on a winner. I totally support that.
I'm fine with bandwagon fans - or whatever you want to call them. The more people in the stands wearing Red, sporting the Curly Dub and cheering on the Nats - the better. Hopefully those of us who have been through the suck will be good about welcoming them aboard and bringing them along for the ride ...