First, I would assume that the 13,000 employees of Hobby Lobby are aware of the religious beliefs of the owners of the company. It took me 5 seconds to get to their website via Google and see "religion" immediately, Nobody is forcing them to work there if they are offended by said beliefs.
Second, how is Hobby Lobby "forcing it's religious beliefs on it's employees" by opposing Obamacare?
Third, it's not just contraceptives, it's also abortion. Unless you've been living in a cave, that's a very hot-button topic.