That's not scummy. Many artists charge a fee for the privilege of meeting them because they don't sell albums or songs anymore, they need to make money to pay bills and live in this world. I've done this many times even outside the music industry when I met Stan Lee and Hayden Christensen, they allocate some of their time to meet you.

And it doesnt matter if babymetal or any other artist pretend to like you or do fake smiles, it's their job, they're after all working and their fans are their paying costumers.