The first game Kanter is a major minus on the floor (in plus minis at least) everyone goes on here to point out asap. The same people didn't point out the games kanter was a + on the floor during those close SA spur games. When +/- supports your argument you use it. When it doesn't you ignore it. Textbook confirmation bias.
Your textbook confirmation bias is not allowing you to objectively see OKC performing worse when Kanter is on the floor. The evidence is overwhelming.
OKC overall is positive, not surprising when you consider that OKC has won 71% in the playoffs. So the fact that Kanter is slightly positive tells you very little. What matters is that they are much more positive with him off the floor.