One is that the test is badly designed. They either ask unrevealing questions or have a lousy algorithm for turning the information into an assessment of how rightwing I am. I think the second is more likely: the questions look divisive enough to me.
The second is that you just can’t tell how rightwing someone is by getting them to fill in a questionnaire. When I first took Simon Baron-Cohen’s empathy test and landed deep in the autistic zone I was a bit taken aback, but then it was pointed out to me that asking people whether they can read minds isn’t a foolproof way of finding out if they can. Maybe political views are like that: people assess their views on the basis of slogans like ‘free trade is fair trade’ and shibboleths like abortion, but this assessment might not be borne out by the positions they take on specific issues when they arise.