I think my issue is less with the idea that property is protected with violence.
The point of the original comic though was that one is justified in using violence to take from the rich because they only have/maintain their property with violence.
But if all property is maintained by violence, am I not then justified in taking any property I see fit? If so, is it free reign to take the property of those whose ability to protect it with violence is minimal? Am I justified in stealing from children or the disabled, since they are protecting their property with the threat of violence?
The fact of the matter is that none of us want to live in that world, so we give over that threat of violence to the state. The state holds a monopoly on violence and notionally uses it to meet out it's use in an equitable and just way.
When the state is bad at that, that can be reason to work towards the restructure of the state, but it's never a reason (imo) to simply violate the law.
Ideally through the civic channels that exist to accomplish change. Run for office. Campaign for reform. Pass the BAR and join a firm that does pro-bono work fighting for important issues.
But if all that fails, there is certainly a point where the people need to rise up and overthrow an unjust government.
But what I'm arguing is never justified is violence against other citizens just because they benefit from the unjust system. If the system is unjust, fix the system, don't lash out at those who just benefit from it.