Kagan didn't recuse herself from the Obamacare case, and she was involved with its creation before she became a Justice.
On top of that, Scalia and Thomas base their rulings on the Constitution. However, Thomas and Scalia do disagree slightly in how they apply their originalist interpretation. For example, Thomas doesn't believe that certain principles, like establishment of religion, even apply to the states.
However, the liberal Justices never disagree on anything. They constantly rule in favor of liberal ideals. You will never see Kagan split from Ginsburg. They always push the same liberal/progressive values.
Shut up Dummies.