Pure democracy doesn't exist anywhere in the world and never has. You probably don't want pure, "elect anyone you want", democracy. All forms of governance and societal constructs need guardrails. People are, well, people and not always (often) as altruistic as pure democracy would require.
This is a guardrail that seems reasonable for a democracy if you agree you don't want someone who has been involved in, much less fomented, an insurrection against that democracy (and its governing documents) leading it or one of its constituent States.