The senate is not Democratic. Senators represent states, not people. Unfortunately the house is very poor at representation as well since the number of seats has been frozen. Too many compromises with slave holders built into the foundation of our country to have anything approaching a functional system. Those compromises have been hampering democracy and progress ever since.
Perhaps you don't understand how voting works? When the difference between minority in favor (not passing) and majority in favor (passing) is one person, then yes, one person has such power.
Democracy doesn't mean that the minority gets to overrule the majority when they feel like it. In fact, it is quite the opposite.
Unfortunately that’s exactly what “democracy” in the US means. Without a super majority, any individual can hold up any legislation they want outside of budget reconciliation. It will be that way as long as the filibuster exists in its current form.