Which One of the SCOTUS Justicies is an Activist?

Question: If a Supreme Court Justice was appointed by a Republican President and they make decisions that the reichwing doesn't like, does that make them "activists" in the derogatory sense (becuase reichwingers usually connote negativity when they use the word "activist")?

Slice:

We found that justices vary widely in their inclination to strike down Congressional laws. Justice Clarence Thomas, appointed by President George H. W. Bush, was the most inclined, voting to invalidate 65.63 percent of those laws; Justice Stephen Breyer, appointed by President Bill Clinton, was the least, voting to invalidate 28.13 percent. The tally for all the justices appears below.

Thomas 65.63 %
Kennedy 64.06 %
Scalia 56.25 %
Rehnquist 46.88 %
O’Connor 46.77 %
Souter 42.19 %
Stevens 39.34 %
Ginsburg 39.06 %
Breyer 28.13 %

One conclusion our data suggests is that those justices often considered more "liberal" - Justices Breyer, Ruth Bader Ginsburg, David Souter and John Paul Stevens - vote least frequently to overturn Congressional statutes, while those often labeled "conservative" vote more frequently to do so. At least by this measure (others are possible, of course), the latter group is the most activist.

To say that a justice is activist under this definition is not itself negative. Because striking down Congressional legislation is sometimes justified, some activism is necessary and proper. We can decide whether a particular degree of activism is appropriate only by assessing the merits of a judge's particular decisions and the judge's underlying constitutional views, which may inspire more or fewer invalidations...