Like the vast majority of American liberals their entire world view regarding politics is performative marches and voting. I doubt one in one hundred of them has ever considered something as simple as chaining the doors of a gun shop closed. And I imagine any time that any of them does independently discover the concept of direct action they're either immediately talked down by their civility loving associates or their energy is coopted by Democrat party functionaries.

I'm sure the deaths of school children are very emotionally upsetting to them, but for all practical intents and purposes the democratic base have no agency and no ability to act.