Jan 6 was planned for MONTHS ahead of time, by a group that already had a wide and organized network of radical agitators. It took years for those groups to get to where they were to pull Jan 6 off. And it still failed. The left doesn't have anywhere close to that level of organization anymore. They used to exist in the labor unions and civil rights groups but the government has systemically targeted and destroyed them. It takes time to rebuild that organization. It's not a matter of "balls".
It doesnt matter. You dont need years of planning to go stand outside of DC with signs. If a sea of people simply show up all with the same message (possibly aided by the already established movements) we'd have a Civil Rights 2: Scared Fascist Boogaloo. But everyone is too afraid of "looking like them".
It's actually incredibly easy to find where these people, or their family members are. It doesn't need to be one large event. It can be death by a thousand cuts