Is it surprising that an appication used to stream torrents, is primarily used for piracy? No, no it's not, and this is why I'm scratching my head. They knew from day one, before they wrote a single line of code that the application would be used for pirating movies. For this reason, I assumed they had a plan, because surely no sane development team would put forth the time to setup this project, and then act surprised at the first legal threat, and close up shop.
I'm not sure surprised is the word I'd use to describe their sentiment. I'd guess rather that they originally planned to back down at the first sign of legal threats. Popcorn Time has been circulated as an experiment, not a business, and in that sense it was a success. Also, the code isn't going anywhere, so it's not as if all this work was for nothing.
But they had a plan - the application is opensource, so anyone can continue it. And since it relies on torrents, killing the swarm is pretty much impossible.
The team that built it isn't acting surprised. I'm a little bit surprised that something more severe didn't happen, such as some of the developers being targeted specifically. All for a product that gets data which is already out there and feeds it to you.