Political scientist: As a political system, democracy does not promote political freedom.
Conclusion
As a political system, democracy does not promote political freedom.
Evidence
Some democracies in history have resulted in some of the most oppressive societies (i.e. the least political freedom). Likewise, there have been enlightened despotisms and oligarchies that have provided a remarkable level of political freedom to their subjects.
Evaluate
This argument feels analogous to saying, .
When we say "X promotes Y", we're not claiming that "X guarantees Y" or that . It's a much weaker claim than that. It's just saying that X has some causal influence on the likelihood of Y.
The author can't cherry-pick democracies that were not free and non-democracies (despotisms and oligarchies) that were free, and conclude from that that democracies don't tend to help political freedom.
Goal
Look for something complaining that the author is trying to write off a causal relationship by cherry-picking a few counterexamples that don't fit the causal relationship.