You're right about who is causing the damage etc. but the 'commons' does not refer to the people; it refers to the shared resource. So a public park is the commons. And when it gets polluted with plastic rubbish etc. because externalities are not internalized that's a tragedy of the commons.
Thanks for both teaching me and not losing the forest for the trees of my point.
The fallacy in "the tragedy of the commons" is that there's something inherent in having a shared resource that dooms the shared resource. At least this is the popular understanding. And I'll add that if we look at shared resources both with more breadth -- e.g. across history and cultures -- and in more depth -- e.g. cross-analysis, they come out looking much more successful than you'd think.