People don't lose their humanity just because they work for (or own) a corporation.
But neither does it extend to the corporation. Aardvarkjoe Catering, LLC doesn't have a religion even if its owner(s) and employee(s) do, and thus can't refuse anything on religious grounds. An employee of Aardvarkjoe Catering, LLC may feel servicing sexual, ethnical, political or other minorities is unacceptable, and if so Aardvarkjoe Catering, LLC must deal with the issue as it sees fit within limits dictated by law; but Aardvarkjoe Catering, LLC is not that employee.
You don't get to put down your corporate shield whenever that suits you, yet hide behind it the rest of the time.