Classifying you as a leftist doesn't mean that you have to agree with other leftists on everything, or that you aren't allowed to have a few opinions that are right-wing too. It just means that your opinions tend to fall on the left side of the spectrum.
In other words, people aren't left wing because they identify as left and then that determines their opinions. They're left wing because, regardless of how they came to their conclusions on what their opinions should be, those opinions are on the left.