Words change their meaning over time. The meaning of democracy has expanded into people voting, usually for representatives but possibly for electors and such and even referendums. Whether some things take a super-majority to pass doesn't take away that the people voted, even if it is indirectly voting for their local government who then votes to amend the Constitution. Limiting who can vote doesn't mean it is not a democracy either, very few democracies allow 16 yr olds to vote.
It is true that your framers set things up so a minority of people can tyrannize the majority (50.1% of voters in the least populous States vote in State governments who want to amend the Constitution taking away the rights of people in the most populous States where 99% voted for State governments against the amendment, or worse if the vote was split in the small States between more parties) but it's still a form of democracy.