Money. Money is why they allowed it. You can trace this all back to the Citizens United decision by the SCOTUS, and beyond. The only way this ends is by reversing that and properly taxing wealth, which won’t happen without a true populist movement. Otherwise, it’ll just be more Adjustors. There is a nonviolent path, but I simply cannot see the wealthy and powerful choosing it.
When your economy (and now, political system, and by extension, judiciary) rewards those who are most amoral and ruthless, violence is necessarily the end result. The only questions are when, how bad, for how long, and who wins.